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-rw-r--r--nixos/doc/manual/configuration/x-windows.xml3
-rw-r--r--nixos/doc/manual/configuration/xfce.xml5
-rw-r--r--nixos/doc/manual/man-nixos-option.xml9
-rw-r--r--nixos/doc/manual/release-notes/rl-2003.xml112
-rw-r--r--nixos/lib/make-ext4-fs.nix44
-rw-r--r--nixos/lib/testing-python.nix3
-rw-r--r--nixos/lib/testing.nix3
-rw-r--r--nixos/modules/config/console.nix203
-rw-r--r--nixos/modules/config/i18n.nix63
-rw-r--r--nixos/modules/installer/cd-dvd/sd-image.nix13
-rw-r--r--nixos/modules/installer/tools/nixos-generate-config.pl3
-rw-r--r--nixos/modules/module-list.nix5
-rw-r--r--nixos/modules/programs/sway.nix3
-rw-r--r--nixos/modules/security/acme.nix4
-rw-r--r--nixos/modules/services/admin/oxidized.nix1
-rw-r--r--nixos/modules/services/backup/postgresql-backup.nix2
-rw-r--r--nixos/modules/services/databases/postgresql.nix4
-rw-r--r--nixos/modules/services/development/lorri.nix2
-rw-r--r--nixos/modules/services/misc/mame.nix67
-rw-r--r--nixos/modules/services/misc/matrix-synapse.nix31
-rw-r--r--nixos/modules/services/networking/3proxy.nix424
-rw-r--r--nixos/modules/services/networking/firewall.nix15
-rw-r--r--nixos/modules/services/networking/helpers.nix11
-rw-r--r--nixos/modules/services/networking/nat.nix5
-rw-r--r--nixos/modules/services/networking/unbound.nix13
-rw-r--r--nixos/modules/services/web-servers/nginx/default.nix31
-rw-r--r--nixos/modules/services/web-servers/nginx/location-options.nix2
-rw-r--r--nixos/modules/services/web-servers/unit/default.nix28
-rw-r--r--nixos/modules/services/x11/desktop-managers/cde.nix55
-rw-r--r--nixos/modules/services/x11/desktop-managers/default.nix25
-rw-r--r--nixos/modules/services/x11/desktop-managers/gnome3.nix4
-rw-r--r--nixos/modules/services/x11/desktop-managers/pantheon.nix8
-rw-r--r--nixos/modules/services/x11/desktop-managers/surf-display.nix2
-rw-r--r--nixos/modules/services/x11/display-managers/account-service-util.nix39
-rw-r--r--nixos/modules/services/x11/display-managers/default.nix251
-rw-r--r--nixos/modules/services/x11/display-managers/gdm.nix62
-rw-r--r--nixos/modules/services/x11/display-managers/lightdm-greeters/mini.nix5
-rw-r--r--nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix3
-rw-r--r--nixos/modules/services/x11/display-managers/lightdm.nix35
-rw-r--r--nixos/modules/services/x11/display-managers/sddm.nix20
-rw-r--r--nixos/modules/services/x11/imwheel.nix68
-rw-r--r--nixos/modules/services/x11/window-managers/default.nix15
-rw-r--r--nixos/modules/tasks/filesystems/nfs.nix6
-rw-r--r--nixos/modules/tasks/kbd.nix127
-rw-r--r--nixos/modules/tasks/network-interfaces-systemd.nix4
-rw-r--r--nixos/modules/virtualisation/container-config.nix1
-rw-r--r--nixos/modules/virtualisation/lxd.nix28
-rw-r--r--nixos/release-combined.nix4
-rw-r--r--nixos/tests/3proxy.nix162
-rw-r--r--nixos/tests/all-tests.nix7
-rw-r--r--nixos/tests/common/x11.nix8
-rw-r--r--nixos/tests/gnome3-xorg.nix2
-rw-r--r--nixos/tests/hadoop/hdfs.nix26
-rw-r--r--nixos/tests/hadoop/yarn.nix24
-rw-r--r--nixos/tests/haproxy.nix16
-rw-r--r--nixos/tests/hitch/default.nix12
-rw-r--r--nixos/tests/i3wm.nix2
-rw-r--r--nixos/tests/initrd-network.nix8
-rw-r--r--nixos/tests/leaps.nix12
-rw-r--r--nixos/tests/lidarr.nix10
-rw-r--r--nixos/tests/lightdm.nix3
-rw-r--r--nixos/tests/mailcatcher.nix16
-rw-r--r--nixos/tests/mutable-users.nix28
-rw-r--r--nixos/tests/mxisd.nix17
-rw-r--r--nixos/tests/nesting.nix36
-rw-r--r--nixos/tests/networking.nix473
-rw-r--r--nixos/tests/nfs.nix90
-rw-r--r--nixos/tests/nfs/default.nix9
-rw-r--r--nixos/tests/nfs/kerberos.nix133
-rw-r--r--nixos/tests/nfs/simple.nix94
-rw-r--r--nixos/tests/nghttpx.nix10
-rw-r--r--nixos/tests/novacomd.nix32
-rw-r--r--nixos/tests/nzbget.nix18
-rw-r--r--nixos/tests/orangefs.nix52
-rw-r--r--nixos/tests/osrm-backend.nix14
-rw-r--r--nixos/tests/overlayfs.nix77
-rw-r--r--nixos/tests/paperless.nix29
-rw-r--r--nixos/tests/pdns-recursor.nix6
-rw-r--r--nixos/tests/peerflix.nix8
-rw-r--r--nixos/tests/pgmanage.nix12
-rw-r--r--nixos/tests/php-pcre.nix9
-rw-r--r--nixos/tests/plasma5.nix2
-rw-r--r--nixos/tests/postgis.nix12
-rw-r--r--nixos/tests/quagga.nix28
-rw-r--r--nixos/tests/rspamd.nix159
-rw-r--r--nixos/tests/sddm.nix6
-rw-r--r--nixos/tests/sonarr.nix8
-rw-r--r--nixos/tests/switch-test.nix10
-rw-r--r--nixos/tests/systemd-timesyncd.nix24
-rw-r--r--nixos/tests/wireguard/namespaces.nix18
-rw-r--r--nixos/tests/xmonad.nix8
-rw-r--r--nixos/tests/zsh-history.nix35
92 files changed, 2464 insertions, 1172 deletions
diff --git a/nixos/doc/manual/configuration/x-windows.xml b/nixos/doc/manual/configuration/x-windows.xml
index 9206f43ea392..55ad9fe6e653 100644
--- a/nixos/doc/manual/configuration/x-windows.xml
+++ b/nixos/doc/manual/configuration/x-windows.xml
@@ -83,8 +83,7 @@
   desktop environment. If you wanted no desktop environment and i3 as your your
   window manager, you'd define:
 <programlisting>
-<xref linkend="opt-services.xserver.desktopManager.default"/> = "none";
-<xref linkend="opt-services.xserver.windowManager.default"/> = "i3";
+<xref linkend="opt-services.xserver.displayManager.defaultSession"/> = "none+i3";
 </programlisting>
   And, finally, to enable auto-login for a user <literal>johndoe</literal>:
 <programlisting>
diff --git a/nixos/doc/manual/configuration/xfce.xml b/nixos/doc/manual/configuration/xfce.xml
index 6ac99c6b2bee..027828bb936d 100644
--- a/nixos/doc/manual/configuration/xfce.xml
+++ b/nixos/doc/manual/configuration/xfce.xml
@@ -7,9 +7,8 @@
  <para>
   To enable the Xfce Desktop Environment, set
 <programlisting>
-<link linkend="opt-services.xserver.desktopManager.default">services.xserver.desktopManager</link> = {
-  <link linkend="opt-services.xserver.desktopManager.xfce.enable">xfce.enable</link> = true;
-  <link linkend="opt-services.xserver.desktopManager.default">default</link> = "xfce";
+<xref linkend="opt-services.xserver.desktopManager.xfce.enable" /> = true;
+<xref linkend="opt-services.xserver.displayManager.defaultSession" /> = "xfce";
 };
 </programlisting>
  </para>
diff --git a/nixos/doc/manual/man-nixos-option.xml b/nixos/doc/manual/man-nixos-option.xml
index beabf020c92a..b82f31256099 100644
--- a/nixos/doc/manual/man-nixos-option.xml
+++ b/nixos/doc/manual/man-nixos-option.xml
@@ -119,4 +119,13 @@ Defined by:
    bug, please report to Nicolas Pierron.
   </para>
  </refsection>
+ <refsection>
+  <title>See also</title>
+  <para>
+   <citerefentry>
+    <refentrytitle>configuration.nix</refentrytitle>
+    <manvolnum>5</manvolnum>
+   </citerefentry>
+  </para>
+ </refsection>
 </refentry>
diff --git a/nixos/doc/manual/release-notes/rl-2003.xml b/nixos/doc/manual/release-notes/rl-2003.xml
index 579b8d537444..5744de96b74b 100644
--- a/nixos/doc/manual/release-notes/rl-2003.xml
+++ b/nixos/doc/manual/release-notes/rl-2003.xml
@@ -55,6 +55,19 @@
       and adding a <option>--all</option> option which prints all options and their values.
     </para>
    </listitem>
+   <listitem>
+    <para>
+     <option>services.xserver.desktopManager.default</option> and <option>services.xserver.windowManager.default</option> options were replaced by a single <xref linkend="opt-services.xserver.displayManager.defaultSession"/> option to improve support for upstream session files. If you used something like:
+<programlisting>
+services.xserver.desktopManager.default = "xfce";
+services.xserver.windowManager.default = "icewm";
+</programlisting>
+     you should change it to:
+<programlisting>
+services.xserver.displayManager.defaultSession = "xfce+icewm";
+</programlisting>
+    </para>
+   </listitem>
   </itemizedlist>
  </section>
 
@@ -127,18 +140,18 @@
    </listitem>
    <listitem>
     <para>
-      The <literal>99-main.network</literal> file was removed. Maching all
-      network interfaces caused many breakages, see
-      <link xlink:href="https://github.com/NixOS/nixpkgs/pull/18962">#18962</link>
-        and <link xlink:href="https://github.com/NixOS/nixpkgs/pull/71106">#71106</link>.
+     The <literal>99-main.network</literal> file was removed. Maching all
+     network interfaces caused many breakages, see
+     <link xlink:href="https://github.com/NixOS/nixpkgs/pull/18962">#18962</link>
+       and <link xlink:href="https://github.com/NixOS/nixpkgs/pull/71106">#71106</link>.
     </para>
     <para>
-      We already don't support the global <link linkend="opt-networking.useDHCP">networking.useDHCP</link>,
-      <link linkend="opt-networking.defaultGateway">networking.defaultGateway</link> and
-      <link linkend="opt-networking.defaultGateway6">networking.defaultGateway6</link> options
-      if <link linkend="opt-networking.useNetworkd">networking.useNetworkd</link> is enabled,
-      but direct users to configure the per-device
-      <link linkend="opt-networking.interfaces">networking.interfaces.&lt;name&gt;.…</link> options.
+     We already don't support the global <link linkend="opt-networking.useDHCP">networking.useDHCP</link>,
+     <link linkend="opt-networking.defaultGateway">networking.defaultGateway</link> and
+     <link linkend="opt-networking.defaultGateway6">networking.defaultGateway6</link> options
+     if <link linkend="opt-networking.useNetworkd">networking.useNetworkd</link> is enabled,
+     but direct users to configure the per-device
+     <link linkend="opt-networking.interfaces">networking.interfaces.&lt;name&gt;.…</link> options.
     </para>
    </listitem>
    <listitem>
@@ -204,6 +217,14 @@
       The <literal>buildRustCrate</literal> infrastructure now produces <literal>lib</literal> outputs in addition to the <literal>out</literal> output.
       This has led to drastically reduced closed sizes for some rust crates since development dependencies are now in the <literal>lib</literal> output.
     </para>
+    </listitem>
+   <listitem>
+    <para>
+     Pango was upgraded to 1.44, which no longer uses freetype for font loading.  This means that type1
+     and bitmap fonts are no longer supported in applications relying on Pango for font rendering
+     (notably, GTK application). See <link xlink:href="https://gitlab.gnome.org/GNOME/pango/issues/386">
+     upstream issue</link> for more information.
+    </para>
    </listitem>
    <listitem>
     <para>
@@ -235,6 +256,65 @@
      choices (whether to perform the action as themselves with wheel permissions, or as the root user).
     </para>
    </listitem>
+   <listitem>
+    <para>
+     NixOS containers no longer build NixOS manual by default. This saves evaluation time,
+     especially if there are many declarative containers defined. Note that this is already done
+     when <literal>&lt;nixos/modules/profiles/minimal.nix&gt;</literal> module is included
+     in container config.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Virtual console options have been reorganized and can be found under
+     a single top-level attribute: <literal>console</literal>.
+     The full set of changes is as follows:
+    </para>
+    <itemizedlist>
+      <listitem>
+       <para>
+         <literal>i18n.consoleFont</literal> renamed to
+         <link linkend="opt-console.font">console.font</link>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+         <literal>i18n.consoleKeyMap</literal> renamed to
+         <link linkend="opt-console.keyMap">console.keyMap</link>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+         <literal>i18n.consoleColors</literal> renamed to
+         <link linkend="opt-console.colors">console.colors</link>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+         <literal>i18n.consolePackages</literal> renamed to
+         <link linkend="opt-console.packages">console.packages</link>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+         <literal>i18n.consoleUseXkbConfig</literal> renamed to
+         <link linkend="opt-console.useXkbConfig">console.useXkbConfig</link>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+         <literal>boot.earlyVconsoleSetup</literal> renamed to
+         <link linkend="opt-console.earlySetup">console.earlySetup</link>
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+         <literal>boot.extraTTYs</literal> renamed to
+         <link linkend="opt-console.extraTTYs">console.extraTTYs</link>
+       </para>
+      </listitem>
+    </itemizedlist>
+   </listitem>
   </itemizedlist>
  </section>
 
@@ -251,6 +331,18 @@
    </listitem>
    <listitem>
     <para>
+     The nginx web server previously started its master process as root
+     privileged, then ran worker processes as a less privileged identity user.
+     This was changed to start all of nginx as a less privileged user (defined by
+     <literal>services.nginx.user</literal> and
+     <literal>services.nginx.group</literal>). As a consequence, all files that
+     are needed for nginx to run (included configuration fragments, SSL
+     certificates and keys, etc.) must now be readable by this less privileged
+     user/group.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
      OpenSSH has been upgraded from 7.9 to 8.1, improving security and adding features
      but with potential incompatibilities.  Consult the
      <link xlink:href="https://www.openssh.com/txt/release-8.1">
diff --git a/nixos/lib/make-ext4-fs.nix b/nixos/lib/make-ext4-fs.nix
index 932adcd97967..f46d3990c06b 100644
--- a/nixos/lib/make-ext4-fs.nix
+++ b/nixos/lib/make-ext4-fs.nix
@@ -4,8 +4,11 @@
 # generated image is sized to only fit its contents, with the expectation
 # that a script resizes the filesystem at boot time.
 { pkgs
+, lib
 # List of derivations to be included
 , storePaths
+# Whether or not to compress the resulting image with zstd
+, compressImage ? false, zstd
 # Shell commands to populate the ./files directory.
 # All files in that directory are copied to the root of the FS.
 , populateImageCommands ? ""
@@ -20,18 +23,20 @@
 let
   sdClosureInfo = pkgs.buildPackages.closureInfo { rootPaths = storePaths; };
 in
-
 pkgs.stdenv.mkDerivation {
-  name = "ext4-fs.img";
+  name = "ext4-fs.img${lib.optionalString compressImage ".zst"}";
 
-  nativeBuildInputs = [e2fsprogs.bin libfaketime perl lkl];
+  nativeBuildInputs = [ e2fsprogs.bin libfaketime perl lkl ]
+  ++ lib.optional compressImage zstd;
 
   buildCommand =
     ''
+      ${if compressImage then "img=temp.img" else "img=$out"}
       (
       mkdir -p ./files
       ${populateImageCommands}
       )
+
       # Add the closures of the top-level store objects.
       storePaths=$(cat ${sdClosureInfo}/store-paths)
 
@@ -42,28 +47,26 @@ pkgs.stdenv.mkDerivation {
       bytes=$((2 * 4096 * $numInodes + 4096 * $numDataBlocks))
       echo "Creating an EXT4 image of $bytes bytes (numInodes=$numInodes, numDataBlocks=$numDataBlocks)"
 
-      truncate -s $bytes $out
-      faketime -f "1970-01-01 00:00:01" mkfs.ext4 -L ${volumeLabel} -U ${uuid} $out
+      truncate -s $bytes $img
+      faketime -f "1970-01-01 00:00:01" mkfs.ext4 -L ${volumeLabel} -U ${uuid} $img
 
       # Also include a manifest of the closures in a format suitable for nix-store --load-db.
       cp ${sdClosureInfo}/registration nix-path-registration
-      cptofs -t ext4 -i $out nix-path-registration /
+      cptofs -t ext4 -i $img nix-path-registration /
 
       # Create nix/store before copying paths
       faketime -f "1970-01-01 00:00:01" mkdir -p nix/store
-      cptofs -t ext4 -i $out nix /
+      cptofs -t ext4 -i $img nix /
 
       echo "copying store paths to image..."
-      cptofs -t ext4 -i $out $storePaths /nix/store/
+      cptofs -t ext4 -i $img $storePaths /nix/store/
 
-      (
       echo "copying files to image..."
-      cd ./files
-      cptofs -t ext4 -i $out ./* /
-      )
+      cptofs -t ext4 -i $img ./files/* /
+
 
       # I have ended up with corrupted images sometimes, I suspect that happens when the build machine's disk gets full during the build.
-      if ! fsck.ext4 -n -f $out; then
+      if ! fsck.ext4 -n -f $img; then
         echo "--- Fsck failed for EXT4 image of $bytes bytes (numInodes=$numInodes, numDataBlocks=$numDataBlocks) ---"
         cat errorlog
         return 1
@@ -71,9 +74,9 @@ pkgs.stdenv.mkDerivation {
 
       (
         # Resizes **snugly** to its actual limits (or closer to)
-        free=$(dumpe2fs $out | grep '^Free blocks:')
-        blocksize=$(dumpe2fs $out | grep '^Block size:')
-        blocks=$(dumpe2fs $out | grep '^Block count:')
+        free=$(dumpe2fs $img | grep '^Free blocks:')
+        blocksize=$(dumpe2fs $img | grep '^Block size:')
+        blocks=$(dumpe2fs $img | grep '^Block count:')
         blocks=$((''${blocks##*:})) # format the number.
         blocksize=$((''${blocksize##*:})) # format the number.
         # System can't boot with 0 blocks free.
@@ -82,10 +85,15 @@ pkgs.stdenv.mkDerivation {
         size=$(( blocks - ''${free##*:} + fudge ))
 
         echo "Resizing from $blocks blocks to $size blocks. (~ $((size*blocksize/1024/1024))MiB)"
-        EXT2FS_NO_MTAB_OK=yes resize2fs $out -f $size
+        EXT2FS_NO_MTAB_OK=yes resize2fs $img -f $size
       )
 
       # And a final fsck, because of the previous truncating.
-      fsck.ext4 -n -f $out
+      fsck.ext4 -n -f $img
+
+      if [ ${builtins.toString compressImage} ]; then
+        echo "Compressing image"
+        zstd -v --no-progress ./$img -o $out
+      fi
     '';
 }
diff --git a/nixos/lib/testing-python.nix b/nixos/lib/testing-python.nix
index d567d2687653..c4eb9328b1db 100644
--- a/nixos/lib/testing-python.nix
+++ b/nixos/lib/testing-python.nix
@@ -262,9 +262,8 @@ in rec {
           virtualisation.memorySize = 1024;
           services.xserver.enable = true;
           services.xserver.displayManager.auto.enable = true;
-          services.xserver.windowManager.default = "icewm";
+          services.xserver.displayManager.defaultSession = "none+icewm";
           services.xserver.windowManager.icewm.enable = true;
-          services.xserver.desktopManager.default = "none";
         };
     in
       runInMachine ({
diff --git a/nixos/lib/testing.nix b/nixos/lib/testing.nix
index a5f060a8d8e3..ae8ecd6270ce 100644
--- a/nixos/lib/testing.nix
+++ b/nixos/lib/testing.nix
@@ -249,9 +249,8 @@ in rec {
           virtualisation.memorySize = 1024;
           services.xserver.enable = true;
           services.xserver.displayManager.auto.enable = true;
-          services.xserver.windowManager.default = "icewm";
+          services.xserver.displayManager.defaultSession = "none+icewm";
           services.xserver.windowManager.icewm.enable = true;
-          services.xserver.desktopManager.default = "none";
         };
     in
       runInMachine ({
diff --git a/nixos/modules/config/console.nix b/nixos/modules/config/console.nix
new file mode 100644
index 000000000000..f662ed62d31d
--- /dev/null
+++ b/nixos/modules/config/console.nix
@@ -0,0 +1,203 @@
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.console;
+
+  makeColor = i: concatMapStringsSep "," (x: "0x" + substring (2*i) 2 x);
+
+  isUnicode = hasSuffix "UTF-8" (toUpper config.i18n.defaultLocale);
+
+  optimizedKeymap = pkgs.runCommand "keymap" {
+    nativeBuildInputs = [ pkgs.buildPackages.kbd ];
+    LOADKEYS_KEYMAP_PATH = "${consoleEnv}/share/keymaps/**";
+    preferLocalBuild = true;
+  } ''
+    loadkeys -b ${optionalString isUnicode "-u"} "${cfg.keyMap}" > $out
+  '';
+
+  # Sadly, systemd-vconsole-setup doesn't support binary keymaps.
+  vconsoleConf = pkgs.writeText "vconsole.conf" ''
+    KEYMAP=${cfg.keyMap}
+    FONT=${cfg.font}
+  '';
+
+  consoleEnv = pkgs.buildEnv {
+    name = "console-env";
+    paths = [ pkgs.kbd ] ++ cfg.packages;
+    pathsToLink = [
+      "/share/consolefonts"
+      "/share/consoletrans"
+      "/share/keymaps"
+      "/share/unimaps"
+    ];
+  };
+
+  setVconsole = !config.boot.isContainer;
+in
+
+{
+  ###### interface
+
+  options.console  = {
+    font = mkOption {
+      type = types.str;
+      default = "Lat2-Terminus16";
+      example = "LatArCyrHeb-16";
+      description = ''
+        The font used for the virtual consoles.  Leave empty to use
+        whatever the <command>setfont</command> program considers the
+        default font.
+      '';
+    };
+
+    keyMap = mkOption {
+      type = with types; either str path;
+      default = "us";
+      example = "fr";
+      description = ''
+        The keyboard mapping table for the virtual consoles.
+      '';
+    };
+
+    colors = mkOption {
+      type = types.listOf types.str;
+      default = [];
+      example = [
+        "002b36" "dc322f" "859900" "b58900"
+        "268bd2" "d33682" "2aa198" "eee8d5"
+        "002b36" "cb4b16" "586e75" "657b83"
+        "839496" "6c71c4" "93a1a1" "fdf6e3"
+      ];
+      description = ''
+        The 16 colors palette used by the virtual consoles.
+        Leave empty to use the default colors.
+        Colors must be in hexadecimal format and listed in
+        order from color 0 to color 15.
+      '';
+
+    };
+
+    packages = mkOption {
+      type = types.listOf types.package;
+      default = with pkgs.kbdKeymaps; [ dvp neo ];
+      defaultText = ''with pkgs.kbdKeymaps; [ dvp neo ]'';
+      description = ''
+        List of additional packages that provide console fonts, keymaps and
+        other resources for virtual consoles use.
+      '';
+    };
+
+    extraTTYs = mkOption {
+      default = [];
+      type = types.listOf types.str;
+      example = ["tty8" "tty9"];
+      description = ''
+        TTY (virtual console) devices, in addition to the consoles on
+        which mingetty and syslogd run, that must be initialised.
+        Only useful if you have some program that you want to run on
+        some fixed console.  For example, the NixOS installation CD
+        opens the manual in a web browser on console 7, so it sets
+        <option>console.extraTTYs</option> to <literal>["tty7"]</literal>.
+      '';
+    };
+
+    useXkbConfig = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        If set, configure the virtual console keymap from the xserver
+        keyboard settings.
+      '';
+    };
+
+    earlySetup = mkOption {
+      default = false;
+      type = types.bool;
+      description = ''
+        Enable setting virtual console options as early as possible (in initrd).
+      '';
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkMerge [
+    { console.keyMap = with config.services.xserver;
+        mkIf cfg.useXkbConfig
+          (pkgs.runCommand "xkb-console-keymap" { preferLocalBuild = true; } ''
+            '${pkgs.ckbcomp}/bin/ckbcomp' -model '${xkbModel}' -layout '${layout}' \
+              -option '${xkbOptions}' -variant '${xkbVariant}' > "$out"
+          '');
+    }
+
+    (mkIf (!setVconsole) {
+      systemd.services.systemd-vconsole-setup.enable = false;
+    })
+
+    (mkIf setVconsole (mkMerge [
+      { environment.systemPackages = [ pkgs.kbd ];
+
+        # Let systemd-vconsole-setup.service do the work of setting up the
+        # virtual consoles.
+        environment.etc."vconsole.conf".source = vconsoleConf;
+        # Provide kbd with additional packages.
+        environment.etc.kbd.source = "${consoleEnv}/share";
+
+        boot.initrd.preLVMCommands = mkBefore ''
+          kbd_mode ${if isUnicode then "-u" else "-a"} -C /dev/console
+          printf "\033%%${if isUnicode then "G" else "@"}" >> /dev/console
+          loadkmap < ${optimizedKeymap}
+
+          ${optionalString cfg.earlySetup ''
+            setfont -C /dev/console $extraUtils/share/consolefonts/font.psf
+          ''}
+        '';
+
+        systemd.services.systemd-vconsole-setup =
+          { before = [ "display-manager.service" ];
+            after = [ "systemd-udev-settle.service" ];
+            restartTriggers = [ vconsoleConf consoleEnv ];
+          };
+      }
+
+      (mkIf (cfg.colors != []) {
+        boot.kernelParams = [
+          "vt.default_red=${makeColor 0 cfg.colors}"
+          "vt.default_grn=${makeColor 1 cfg.colors}"
+          "vt.default_blu=${makeColor 2 cfg.colors}"
+        ];
+      })
+
+      (mkIf cfg.earlySetup {
+        boot.initrd.extraUtilsCommands = ''
+          mkdir -p $out/share/consolefonts
+          ${if substring 0 1 cfg.font == "/" then ''
+            font="${cfg.font}"
+          '' else ''
+            font="$(echo ${consoleEnv}/share/consolefonts/${cfg.font}.*)"
+          ''}
+          if [[ $font == *.gz ]]; then
+            gzip -cd $font > $out/share/consolefonts/font.psf
+          else
+            cp -L $font $out/share/consolefonts/font.psf
+          fi
+        '';
+      })
+    ]))
+  ];
+
+  imports = [
+    (mkRenamedOptionModule [ "i18n" "consoleFont" ] [ "console" "font" ])
+    (mkRenamedOptionModule [ "i18n" "consoleKeyMap" ] [ "console" "keyMap" ])
+    (mkRenamedOptionModule [ "i18n" "consoleColors" ] [ "console" "colors" ])
+    (mkRenamedOptionModule [ "i18n" "consolePackages" ] [ "console" "packages" ])
+    (mkRenamedOptionModule [ "i18n" "consoleUseXkbConfig" ] [ "console" "useXkbConfig" ])
+    (mkRenamedOptionModule [ "boot" "earlyVconsoleSetup" ] [ "console" "earlySetup" ])
+    (mkRenamedOptionModule [ "boot" "extraTTYs" ] [ "console" "extraTTYs" ])
+  ];
+}
diff --git a/nixos/modules/config/i18n.nix b/nixos/modules/config/i18n.nix
index d0db8fedecd8..45691f4839c8 100644
--- a/nixos/modules/config/i18n.nix
+++ b/nixos/modules/config/i18n.nix
@@ -58,62 +58,6 @@ with lib;
         '';
       };
 
-      consolePackages = mkOption {
-        type = types.listOf types.package;
-        default = with pkgs.kbdKeymaps; [ dvp neo ];
-        defaultText = ''with pkgs.kbdKeymaps; [ dvp neo ]'';
-        description = ''
-          List of additional packages that provide console fonts, keymaps and
-          other resources.
-        '';
-      };
-
-      consoleFont = mkOption {
-        type = types.str;
-        default = "Lat2-Terminus16";
-        example = "LatArCyrHeb-16";
-        description = ''
-          The font used for the virtual consoles.  Leave empty to use
-          whatever the <command>setfont</command> program considers the
-          default font.
-        '';
-      };
-
-      consoleUseXkbConfig = mkOption {
-        type = types.bool;
-        default = false;
-        description = ''
-          If set, configure the console keymap from the xserver keyboard
-          settings.
-        '';
-      };
-
-      consoleKeyMap = mkOption {
-        type = with types; either str path;
-        default = "us";
-        example = "fr";
-        description = ''
-          The keyboard mapping table for the virtual consoles.
-        '';
-      };
-
-      consoleColors = mkOption {
-        type = types.listOf types.str;
-        default = [];
-        example = [
-          "002b36" "dc322f" "859900" "b58900"
-          "268bd2" "d33682" "2aa198" "eee8d5"
-          "002b36" "cb4b16" "586e75" "657b83"
-          "839496" "6c71c4" "93a1a1" "fdf6e3"
-        ];
-        description = ''
-          The 16 colors palette used by the virtual consoles.
-          Leave empty to use the default colors.
-          Colors must be in hexadecimal format and listed in
-          order from color 0 to color 15.
-        '';
-      };
-
     };
 
   };
@@ -123,13 +67,6 @@ with lib;
 
   config = {
 
-    i18n.consoleKeyMap = with config.services.xserver;
-      mkIf config.i18n.consoleUseXkbConfig
-        (pkgs.runCommand "xkb-console-keymap" { preferLocalBuild = true; } ''
-          '${pkgs.ckbcomp}/bin/ckbcomp' -model '${xkbModel}' -layout '${layout}' \
-            -option '${xkbOptions}' -variant '${xkbVariant}' > "$out"
-        '');
-
     environment.systemPackages =
       optional (config.i18n.supportedLocales != []) config.i18n.glibcLocales;
 
diff --git a/nixos/modules/installer/cd-dvd/sd-image.nix b/nixos/modules/installer/cd-dvd/sd-image.nix
index 7865b767f0b7..901c60befb6c 100644
--- a/nixos/modules/installer/cd-dvd/sd-image.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image.nix
@@ -18,6 +18,7 @@ with lib;
 let
   rootfsImage = pkgs.callPackage ../../../lib/make-ext4-fs.nix ({
     inherit (config.sdImage) storePaths;
+    compressImage = true;
     populateImageCommands = config.sdImage.populateRootCommands;
     volumeLabel = "NIXOS_SD";
   } // optionalAttrs (config.sdImage.rootPartitionUUID != null) {
@@ -128,10 +129,11 @@ in
 
     sdImage.storePaths = [ config.system.build.toplevel ];
 
-    system.build.sdImage = pkgs.callPackage ({ stdenv, dosfstools, e2fsprogs, mtools, libfaketime, utillinux, bzip2 }: stdenv.mkDerivation {
+    system.build.sdImage = pkgs.callPackage ({ stdenv, dosfstools, e2fsprogs,
+    mtools, libfaketime, utillinux, bzip2, zstd }: stdenv.mkDerivation {
       name = config.sdImage.imageName;
 
-      nativeBuildInputs = [ dosfstools e2fsprogs mtools libfaketime utillinux bzip2 ];
+      nativeBuildInputs = [ dosfstools e2fsprogs mtools libfaketime utillinux bzip2 zstd ];
 
       inherit (config.sdImage) compressImage;
 
@@ -146,11 +148,14 @@ in
           echo "file sd-image $img" >> $out/nix-support/hydra-build-products
         fi
 
+        echo "Decompressing rootfs image"
+        zstd -d --no-progress "${rootfsImage}" -o ./root-fs.img
+
         # Gap in front of the first partition, in MiB
         gap=8
 
         # Create the image file sized to fit /boot/firmware and /, plus slack for the gap.
-        rootSizeBlocks=$(du -B 512 --apparent-size ${rootfsImage} | awk '{ print $1 }')
+        rootSizeBlocks=$(du -B 512 --apparent-size ./root-fs.img | awk '{ print $1 }')
         firmwareSizeBlocks=$((${toString config.sdImage.firmwareSize} * 1024 * 1024 / 512))
         imageSize=$((rootSizeBlocks * 512 + firmwareSizeBlocks * 512 + gap * 1024 * 1024))
         truncate -s $imageSize $img
@@ -168,7 +173,7 @@ in
 
         # Copy the rootfs into the SD image
         eval $(partx $img -o START,SECTORS --nr 2 --pairs)
-        dd conv=notrunc if=${rootfsImage} of=$img seek=$START count=$SECTORS
+        dd conv=notrunc if=./root-fs.img of=$img seek=$START count=$SECTORS
 
         # Create a FAT32 /boot/firmware partition of suitable size into firmware_part.img
         eval $(partx $img -o START,SECTORS --nr 1 --pairs)
diff --git a/nixos/modules/installer/tools/nixos-generate-config.pl b/nixos/modules/installer/tools/nixos-generate-config.pl
index f2ffe61c42cb..7f98756a7d9f 100644
--- a/nixos/modules/installer/tools/nixos-generate-config.pl
+++ b/nixos/modules/installer/tools/nixos-generate-config.pl
@@ -335,6 +335,9 @@ if (@swaps) {
         next unless -e $swapFilename;
         my $dev = findStableDevPath $swapFilename;
         if ($swapType =~ "partition") {
+            # zram devices are more likely created by configuration.nix, so
+            # ignore them here
+            next if ($swapFilename =~ /^\/dev\/zram/);
             push @swapDevices, "{ device = \"$dev\"; }";
         } elsif ($swapType =~ "file") {
             # swap *files* are more likely specified in configuration.nix, so
diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index bb217d873bb5..7650da89cbdd 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -11,6 +11,7 @@
   ./config/xdg/mime.nix
   ./config/xdg/portal.nix
   ./config/appstream.nix
+  ./config/console.nix
   ./config/xdg/sounds.nix
   ./config/gtk/gtk-icon-cache.nix
   ./config/gnu.nix
@@ -443,6 +444,7 @@
   ./services/misc/logkeys.nix
   ./services/misc/leaps.nix
   ./services/misc/lidarr.nix
+  ./services/misc/mame.nix
   ./services/misc/mathics.nix
   ./services/misc/matrix-synapse.nix
   ./services/misc/mbpfan.nix
@@ -556,6 +558,7 @@
   ./services/network-filesystems/yandex-disk.nix
   ./services/network-filesystems/xtreemfs.nix
   ./services/network-filesystems/ceph.nix
+  ./services/networking/3proxy.nix
   ./services/networking/amuled.nix
   ./services/networking/aria2.nix
   ./services/networking/asterisk.nix
@@ -866,6 +869,7 @@
   ./services/x11/hardware/digimend.nix
   ./services/x11/hardware/cmt.nix
   ./services/x11/gdk-pixbuf.nix
+  ./services/x11/imwheel.nix
   ./services/x11/redshift.nix
   ./services/x11/urxvtd.nix
   ./services/x11/window-managers/awesome.nix
@@ -936,7 +940,6 @@
   ./tasks/filesystems/vfat.nix
   ./tasks/filesystems/xfs.nix
   ./tasks/filesystems/zfs.nix
-  ./tasks/kbd.nix
   ./tasks/lvm.nix
   ./tasks/network-interfaces.nix
   ./tasks/network-interfaces-systemd.nix
diff --git a/nixos/modules/programs/sway.nix b/nixos/modules/programs/sway.nix
index f92d09a7ef44..d685a5259324 100644
--- a/nixos/modules/programs/sway.nix
+++ b/nixos/modules/programs/sway.nix
@@ -24,6 +24,7 @@ let
   swayJoined = pkgs.symlinkJoin {
     name = "sway-joined";
     paths = [ swayWrapped swayPackage ];
+    passthru.providedSessions = [ "sway" ];
   };
 in {
   options.programs.sway = {
@@ -87,6 +88,8 @@ in {
     hardware.opengl.enable = mkDefault true;
     fonts.enableDefaultFonts = mkDefault true;
     programs.dconf.enable = mkDefault true;
+    # To make a Sway session available if a display manager like SDDM is enabled:
+    services.xserver.displayManager.sessionPackages = [ swayJoined ];
   };
 
   meta.maintainers = with lib.maintainers; [ gnidorah primeos colemickens ];
diff --git a/nixos/modules/security/acme.nix b/nixos/modules/security/acme.nix
index 8b7d12552ed5..890c421b0ea9 100644
--- a/nixos/modules/security/acme.nix
+++ b/nixos/modules/security/acme.nix
@@ -241,9 +241,9 @@ in
                     StateDirectoryMode = rights;
                     WorkingDirectory = "/var/lib/${lpath}";
                     ExecStart = "${pkgs.simp_le}/bin/simp_le ${escapeShellArgs cmdline}";
-                    ExecStopPost =
+                    ExecStartPost =
                       let
-                        script = pkgs.writeScript "acme-post-stop" ''
+                        script = pkgs.writeScript "acme-post-start" ''
                           #!${pkgs.runtimeShell} -e
                           ${data.postRun}
                         '';
diff --git a/nixos/modules/services/admin/oxidized.nix b/nixos/modules/services/admin/oxidized.nix
index da81be3f23e8..885eaed1de6f 100644
--- a/nixos/modules/services/admin/oxidized.nix
+++ b/nixos/modules/services/admin/oxidized.nix
@@ -111,6 +111,7 @@ in
         Restart  = "always";
         WorkingDirectory = cfg.dataDir;
         KillSignal = "SIGKILL";
+        PIDFile = "${cfg.dataDir}.config/oxidized/pid";
       };
     };
   };
diff --git a/nixos/modules/services/backup/postgresql-backup.nix b/nixos/modules/services/backup/postgresql-backup.nix
index e768d1b9918a..580c7ce68f1d 100644
--- a/nixos/modules/services/backup/postgresql-backup.nix
+++ b/nixos/modules/services/backup/postgresql-backup.nix
@@ -89,7 +89,7 @@ in {
 
       pgdumpOptions = mkOption {
         type = types.separatedString " ";
-        default = "-Cbo";
+        default = "-C";
         description = ''
           Command line options for pg_dump. This options is not used
           if <literal>config.services.postgresqlBackup.backupAll</literal> is enabled.
diff --git a/nixos/modules/services/databases/postgresql.nix b/nixos/modules/services/databases/postgresql.nix
index 3bedfe96a180..c8fdd89d0d8f 100644
--- a/nixos/modules/services/databases/postgresql.nix
+++ b/nixos/modules/services/databases/postgresql.nix
@@ -339,9 +339,9 @@ in
             '') cfg.ensureDatabases}
           '' + ''
             ${concatMapStrings (user: ''
-              $PSQL -tAc "SELECT 1 FROM pg_roles WHERE rolname='${user.name}'" | grep -q 1 || $PSQL -tAc "CREATE USER ${user.name}"
+              $PSQL -tAc "SELECT 1 FROM pg_roles WHERE rolname='${user.name}'" | grep -q 1 || $PSQL -tAc 'CREATE USER "${user.name}"'
               ${concatStringsSep "\n" (mapAttrsToList (database: permission: ''
-                $PSQL -tAc 'GRANT ${permission} ON ${database} TO ${user.name}'
+                $PSQL -tAc 'GRANT ${permission} ON ${database} TO "${user.name}"'
               '') user.ensurePermissions)}
             '') cfg.ensureUsers}
           '';
diff --git a/nixos/modules/services/development/lorri.nix b/nixos/modules/services/development/lorri.nix
index 68264ee869d1..c843aa56d133 100644
--- a/nixos/modules/services/development/lorri.nix
+++ b/nixos/modules/services/development/lorri.nix
@@ -32,7 +32,7 @@ in {
       description = "Lorri Daemon";
       requires = [ "lorri.socket" ];
       after = [ "lorri.socket" ];
-      path = with pkgs; [ config.nix.package gnutar gzip ];
+      path = with pkgs; [ config.nix.package git gnutar gzip ];
       serviceConfig = {
         ExecStart = "${pkgs.lorri}/bin/lorri daemon";
         PrivateTmp = true;
diff --git a/nixos/modules/services/misc/mame.nix b/nixos/modules/services/misc/mame.nix
new file mode 100644
index 000000000000..c5d5e9e48371
--- /dev/null
+++ b/nixos/modules/services/misc/mame.nix
@@ -0,0 +1,67 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.mame;
+  mame = "mame${lib.optionalString pkgs.stdenv.is64bit "64"}";
+in
+{
+  options = {
+    services.mame = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to setup TUN/TAP Ethernet interface for MAME emulator.
+        '';
+      };
+      user = mkOption {
+        type = types.str;
+        description = ''
+          User from which you run MAME binary.
+        '';
+      };
+      hostAddr = mkOption {
+        type = types.str;
+        description = ''
+          IP address of the host system. Usually an address of the main network
+          adapter or the adapter through which you get an internet connection.
+        '';
+        example = "192.168.31.156";
+      };
+      emuAddr = mkOption {
+        type = types.str;
+        description = ''
+          IP address of the guest system. The same you set inside guest OS under
+          MAME. Should be on the same subnet as <option>services.mame.hostAddr</option>.
+        '';
+        example = "192.168.31.155";
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = [ pkgs.mame ];
+
+    security.wrappers."${mame}" = {
+      source = "${pkgs.mame}/bin/${mame}";
+      capabilities = "cap_net_admin,cap_net_raw+eip";
+    };
+
+    systemd.services.mame = {
+      description = "MAME TUN/TAP Ethernet interface";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      path = [ pkgs.iproute ];
+      serviceConfig = {
+        Type = "oneshot";
+        RemainAfterExit = true;
+        ExecStart = "${pkgs.mame}/bin/taputil.sh -c ${cfg.user} ${cfg.emuAddr} ${cfg.hostAddr} -";
+        ExecStop = "${pkgs.mame}/bin/taputil.sh -d ${cfg.user}";
+      };
+    };
+  };
+
+  meta.maintainers = with lib.maintainers; [ gnidorah ];
+}
diff --git a/nixos/modules/services/misc/matrix-synapse.nix b/nixos/modules/services/misc/matrix-synapse.nix
index 50661b873f64..0bda8980720d 100644
--- a/nixos/modules/services/misc/matrix-synapse.nix
+++ b/nixos/modules/services/misc/matrix-synapse.nix
@@ -671,43 +671,30 @@ in {
         gid = config.ids.gids.matrix-synapse;
       } ];
 
-    services.postgresql.enable = mkIf usePostgresql (mkDefault true);
+    services.postgresql = mkIf (usePostgresql && cfg.create_local_database) {
+      enable = mkDefault true;
+      ensureDatabases = [ cfg.database_name ];
+      ensureUsers = [{
+        name = cfg.database_user;
+        ensurePermissions = { "DATABASE \"${cfg.database_name}\"" = "ALL PRIVILEGES"; };
+      }];
+    };
 
     systemd.services.matrix-synapse = {
       description = "Synapse Matrix homeserver";
-      after = [ "network.target" "postgresql.service" ];
+      after = [ "network.target" ] ++ lib.optional config.services.postgresql.enable "postgresql.service" ;
       wantedBy = [ "multi-user.target" ];
       preStart = ''
         ${cfg.package}/bin/homeserver \
           --config-path ${configFile} \
           --keys-directory ${cfg.dataDir} \
           --generate-keys
-      '' + optionalString (usePostgresql && cfg.create_local_database) ''
-        if ! test -e "${cfg.dataDir}/db-created"; then
-          ${pkgs.sudo}/bin/sudo -u ${pg.superUser} \
-            ${pg.package}/bin/createuser \
-            --login \
-            --no-createdb \
-            --no-createrole \
-            --encrypted \
-            ${cfg.database_user}
-          ${pkgs.sudo}/bin/sudo -u ${pg.superUser} \
-            ${pg.package}/bin/createdb \
-            --owner=${cfg.database_user} \
-            --encoding=UTF8 \
-            --lc-collate=C \
-            --lc-ctype=C \
-            --template=template0 \
-            ${cfg.database_name}
-          touch "${cfg.dataDir}/db-created"
-        fi
       '';
       serviceConfig = {
         Type = "notify";
         User = "matrix-synapse";
         Group = "matrix-synapse";
         WorkingDirectory = cfg.dataDir;
-        PermissionsStartOnly = true;
         ExecStart = ''
           ${cfg.package}/bin/homeserver \
             ${ concatMapStringsSep "\n  " (x: "--config-path ${x} \\") ([ configFile ] ++ cfg.extraConfigFiles) }
diff --git a/nixos/modules/services/networking/3proxy.nix b/nixos/modules/services/networking/3proxy.nix
new file mode 100644
index 000000000000..26aa16679467
--- /dev/null
+++ b/nixos/modules/services/networking/3proxy.nix
@@ -0,0 +1,424 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+  pkg = pkgs._3proxy;
+  cfg = config.services._3proxy;
+  optionalList = list: if list == [ ] then "*" else concatMapStringsSep "," toString list;
+in {
+  options.services._3proxy = {
+    enable = mkEnableOption "3proxy";
+    confFile = mkOption {
+      type = types.path;
+      example = "/var/lib/3proxy/3proxy.conf";
+      description = ''
+        Ignore all other 3proxy options and load configuration from this file.
+      '';
+    };
+    usersFile = mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      example = "/var/lib/3proxy/3proxy.passwd";
+      description = ''
+        Load users and passwords from this file.
+
+        Example users file with plain-text passwords:
+
+        <literal>
+          test1:CL:password1
+          test2:CL:password2
+        </literal>
+
+        Example users file with md5-crypted passwords:
+
+        <literal>
+          test1:CR:$1$tFkisVd2$1GA8JXkRmTXdLDytM/i3a1
+          test2:CR:$1$rkpibm5J$Aq1.9VtYAn0JrqZ8M.1ME.
+        </literal>
+
+        You can generate md5-crypted passwords via https://unix4lyfe.org/crypt/
+        Note that htpasswd tool generates incompatible md5-crypted passwords.
+        Consult <link xlink:href="https://github.com/z3APA3A/3proxy/wiki/How-To-(incomplete)#USERS">documentation</link> for more information.
+      '';
+    };
+    services = mkOption {
+      type = types.listOf (types.submodule {
+        options = {
+          type = mkOption {
+            type = types.enum [
+              "proxy"
+              "socks"
+              "pop3p"
+              "ftppr"
+              "admin"
+              "dnspr"
+              "tcppm"
+              "udppm"
+            ];
+            example = "proxy";
+            description = ''
+              Service type. The following values are valid:
+
+              <itemizedlist>
+                <listitem><para>
+                  <literal>"proxy"</literal>: HTTP/HTTPS proxy (default port 3128).
+                </para></listitem>
+                <listitem><para>
+                  <literal>"socks"</literal>: SOCKS 4/4.5/5 proxy (default port 1080).
+                </para></listitem>
+                <listitem><para>
+                  <literal>"pop3p"</literal>: POP3 proxy (default port 110).
+                </para></listitem>
+                <listitem><para>
+                  <literal>"ftppr"</literal>: FTP proxy (default port 21).
+                </para></listitem>
+                <listitem><para>
+                  <literal>"admin"</literal>: Web interface (default port 80).
+                </para></listitem>
+                <listitem><para>
+                  <literal>"dnspr"</literal>: Caching DNS proxy (default port 53).
+                </para></listitem>
+                <listitem><para>
+                  <literal>"tcppm"</literal>: TCP portmapper.
+                </para></listitem>
+                <listitem><para>
+                  <literal>"udppm"</literal>: UDP portmapper.
+                </para></listitem>
+              </itemizedlist>
+            '';
+          };
+          bindAddress = mkOption {
+            type = types.str;
+            default = "[::]";
+            example = "127.0.0.1";
+            description = ''
+              Address used for service.
+            '';
+          };
+          bindPort = mkOption {
+            type = types.nullOr types.int;
+            default = null;
+            example = 3128;
+            description = ''
+              Override default port used for service.
+            '';
+          };
+          maxConnections = mkOption {
+            type = types.int;
+            default = 100;
+            example = 1000;
+            description = ''
+              Maximum number of simulationeous connections to this service.
+            '';
+          };
+          auth = mkOption {
+            type = types.listOf (types.enum [ "none" "iponly" "strong" ]);
+            example = [ "iponly" "strong" ];
+            description = ''
+              Authentication type. The following values are valid:
+
+              <itemizedlist>
+                <listitem><para>
+                  <literal>"none"</literal>: disables both authentication and authorization. You can not use ACLs.
+                </para></listitem>
+                <listitem><para>
+                  <literal>"iponly"</literal>: specifies no authentication. ACLs authorization is used.
+                </para></listitem>
+                <listitem><para>
+                  <literal>"strong"</literal>: authentication by username/password. If user is not registered his access is denied regardless of ACLs.
+                </para></listitem>
+              </itemizedlist>
+
+              Double authentication is possible, e.g.
+
+              <literal>
+                {
+                  auth = [ "iponly" "strong" ];
+                  acl = [
+                    {
+                      rule = "allow";
+                      targets = [ "192.168.0.0/16" ];
+                    }
+                    {
+                      rule = "allow"
+                      users = [ "user1" "user2" ];
+                    }
+                  ];
+                }
+              </literal>
+              In this example strong username authentication is not required to access 192.168.0.0/16.
+            '';
+          };
+          acl = mkOption {
+            type = types.listOf (types.submodule {
+              options = {
+                rule = mkOption {
+                  type = types.enum [ "allow" "deny" ];
+                  example = "allow";
+                  description = ''
+                    ACL rule. The following values are valid:
+
+                    <itemizedlist>
+                      <listitem><para>
+                        <literal>"allow"</literal>: connections allowed.
+                      </para></listitem>
+                      <listitem><para>
+                        <literal>"deny"</literal>: connections not allowed.
+                      </para></listitem>
+                    </itemizedlist>
+                  '';
+                };
+                users = mkOption {
+                  type = types.listOf types.str;
+                  default = [ ];
+                  example = [ "user1" "user2" "user3" ];
+                  description = ''
+                    List of users, use empty list for any.
+                  '';
+                };
+                sources = mkOption {
+                  type = types.listOf types.str;
+                  default = [ ];
+                  example = [ "127.0.0.1" "192.168.1.0/24" ];
+                  description = ''
+                    List of source IP range, use empty list for any.
+                  '';
+                };
+                targets = mkOption {
+                  type = types.listOf types.str;
+                  default = [ ];
+                  example = [ "127.0.0.1" "192.168.1.0/24" ];
+                  description = ''
+                    List of target IP ranges, use empty list for any.
+                    May also contain host names instead of addresses.
+                    It's possible to use wildmask in the begginning and in the the end of hostname, e.g. *badsite.com or *badcontent*.
+                    Hostname is only checked if hostname presents in request.
+                  '';
+                };
+                targetPorts = mkOption {
+                  type = types.listOf types.int;
+                  default = [ ];
+                  example = [ 80 443 ];
+                  description = ''
+                    List of target ports, use empty list for any.
+                  '';
+                };
+              };
+            });
+            default = [ ];
+            example = literalExample ''
+              [
+                {
+                  rule = "allow";
+                  users = [ "user1" ];
+                }
+                {
+                  rule = "allow";
+                  sources = [ "192.168.1.0/24" ];
+                }
+                {
+                  rule = "deny";
+                }
+              ]
+            '';
+            description = ''
+              Use this option to limit user access to resources.
+            '';
+          };
+          extraArguments = mkOption {
+            type = types.nullOr types.str;
+            default = null;
+            example = "-46";
+            description = ''
+              Extra arguments for service.
+              Consult "Options" section in <link xlink:href="https://github.com/z3APA3A/3proxy/wiki/3proxy.cfg">documentation</link> for available arguments.
+            '';
+          };
+          extraConfig = mkOption {
+            type = types.nullOr types.lines;
+            default = null;
+            description = ''
+              Extra configuration for service. Use this to configure things like bandwidth limiter or ACL-based redirection.
+              Consult <link xlink:href="https://github.com/z3APA3A/3proxy/wiki/3proxy.cfg">documentation</link> for available options.
+            '';
+          };
+        };
+      });
+      default = [ ];
+      example = literalExample ''
+        [
+          {
+            type = "proxy";
+            bindAddress = "192.168.1.24";
+            bindPort = 3128;
+            auth = [ "none" ];
+          }
+          {
+            type = "proxy";
+            bindAddress = "10.10.1.20";
+            bindPort = 3128;
+            auth = [ "iponly" ];
+          }
+          {
+            type = "socks";
+            bindAddress = "172.17.0.1";
+            bindPort = 1080;
+            auth = [ "strong" ];
+          }
+        ]
+      '';
+      description = ''
+        Use this option to define 3proxy services.
+      '';
+    };
+    denyPrivate = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Whether to deny access to private IP ranges including loopback.
+      '';
+    };
+    privateRanges = mkOption {
+      type = types.listOf types.str;
+      default = [
+        "0.0.0.0/8"
+        "127.0.0.0/8"
+        "10.0.0.0/8"
+        "100.64.0.0/10"
+        "172.16.0.0/12"
+        "192.168.0.0/16"
+        "::"
+        "::1"
+        "fc00::/7"
+      ];
+      example = [
+        "0.0.0.0/8"
+        "127.0.0.0/8"
+        "10.0.0.0/8"
+        "100.64.0.0/10"
+        "172.16.0.0/12"
+        "192.168.0.0/16"
+        "::"
+        "::1"
+        "fc00::/7"
+      ];
+      description = ''
+        What IP ranges to deny access when denyPrivate is set tu true.
+      '';
+    };
+    resolution = mkOption {
+      type = types.submodule {
+        options = {
+          nserver = mkOption {
+            type = types.listOf types.str;
+            default = [ ];
+            example = [ "127.0.0.53" "192.168.1.3:5353/tcp" ];
+            description = ''
+              List of nameservers to use.
+
+              Up to 5 nservers may be specified. If no nserver is configured,
+              default system name resolution functions are used.
+            '';
+          };
+          nscache = mkOption {
+            type = types.int;
+            default = 65535;
+            example = 65535;
+            description = "Set name cache size for IPv4.";
+          };
+          nscache6 = mkOption {
+            type = types.int;
+            default = 65535;
+            example = 65535;
+            description = "Set name cache size for IPv6.";
+          };
+          nsrecord = mkOption {
+            type = types.attrsOf types.str;
+            default = { };
+            example = {
+              "files.local" = "192.168.1.12";
+              "site.local" = "192.168.1.43";
+            };
+            description = "Adds static nsrecords.";
+          };
+        };
+      };
+      default = { };
+      description = ''
+        Use this option to configure name resolution and DNS caching.
+      '';
+    };
+    extraConfig = mkOption {
+      type = types.nullOr types.lines;
+      default = null;
+      description = ''
+        Extra configuration, appended to the 3proxy configuration file.
+        Consult <link xlink:href="https://github.com/z3APA3A/3proxy/wiki/3proxy.cfg">documentation</link> for available options.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services._3proxy.confFile = mkDefault (pkgs.writeText "3proxy.conf" ''
+      # log to stdout
+      log
+
+      ${concatMapStringsSep "\n" (x: "nserver " + x) cfg.resolution.nserver}
+
+      nscache ${toString cfg.resolution.nscache}
+      nscache6 ${toString cfg.resolution.nscache6}
+
+      ${concatMapStringsSep "\n" (x: "nsrecord " + x)
+      (mapAttrsToList (name: value: "${name} ${value}")
+        cfg.resolution.nsrecord)}
+
+      ${optionalString (cfg.usersFile != null)
+        ''users $"${cfg.usersFile}"''
+      }
+
+      ${concatMapStringsSep "\n" (service: ''
+        auth ${concatStringsSep " " service.auth}
+
+        ${optionalString (cfg.denyPrivate)
+        "deny * * ${optionalList cfg.privateRanges}"}
+
+        ${concatMapStringsSep "\n" (acl:
+          "${acl.rule} ${
+            concatMapStringsSep " " optionalList [
+              acl.users
+              acl.sources
+              acl.targets
+              acl.targetPorts
+            ]
+          }") service.acl}
+
+        maxconn ${toString service.maxConnections}
+
+        ${optionalString (service.extraConfig != null) service.extraConfig}
+
+        ${service.type} -i${toString service.bindAddress} ${
+          optionalString (service.bindPort != null)
+          "-p${toString service.bindPort}"
+        } ${
+          optionalString (service.extraArguments != null) service.extraArguments
+        }
+
+        flush
+      '') cfg.services}
+      ${optionalString (cfg.extraConfig != null) cfg.extraConfig}
+    '');
+    systemd.services."3proxy" = {
+      description = "Tiny free proxy server";
+      documentation = [ "https://github.com/z3APA3A/3proxy/wiki" ];
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        DynamicUser = true;
+        StateDirectory = "3proxy";
+        ExecStart = "${pkg}/bin/3proxy ${cfg.confFile}";
+        Restart = "on-failure";
+      };
+    };
+  };
+
+  meta.maintainers = with maintainers; [ misuzu ];
+}
diff --git a/nixos/modules/services/networking/firewall.nix b/nixos/modules/services/networking/firewall.nix
index 5919962837a2..15aaf7410674 100644
--- a/nixos/modules/services/networking/firewall.nix
+++ b/nixos/modules/services/networking/firewall.nix
@@ -42,16 +42,7 @@ let
 
   kernelHasRPFilter = ((kernel.config.isEnabled or (x: false)) "IP_NF_MATCH_RPFILTER") || (kernel.features.netfilterRPFilter or false);
 
-  helpers =
-    ''
-      # Helper command to manipulate both the IPv4 and IPv6 tables.
-      ip46tables() {
-        iptables -w "$@"
-        ${optionalString config.networking.enableIPv6 ''
-          ip6tables -w "$@"
-        ''}
-      }
-    '';
+  helpers = import ./helpers.nix { inherit config lib; };
 
   writeShScript = name: text: let dir = pkgs.writeScriptBin name ''
     #! ${pkgs.runtimeShell} -e
@@ -271,7 +262,7 @@ let
       apply = canonicalizePortList;
       example = [ 22 80 ];
       description =
-        '' 
+        ''
           List of TCP ports on which incoming connections are
           accepted.
         '';
@@ -282,7 +273,7 @@ let
       default = [ ];
       example = [ { from = 8999; to = 9003; } ];
       description =
-        '' 
+        ''
           A range of TCP ports on which incoming connections are
           accepted.
         '';
diff --git a/nixos/modules/services/networking/helpers.nix b/nixos/modules/services/networking/helpers.nix
new file mode 100644
index 000000000000..d7d42de0e3a8
--- /dev/null
+++ b/nixos/modules/services/networking/helpers.nix
@@ -0,0 +1,11 @@
+{ config, lib, ... }: ''
+  # Helper command to manipulate both the IPv4 and IPv6 tables.
+  ip46tables() {
+    iptables -w "$@"
+    ${
+      lib.optionalString config.networking.enableIPv6 ''
+        ip6tables -w "$@"
+      ''
+    }
+  }
+''
diff --git a/nixos/modules/services/networking/nat.nix b/nixos/modules/services/networking/nat.nix
index c80db8472f0d..f1238bc6b168 100644
--- a/nixos/modules/services/networking/nat.nix
+++ b/nixos/modules/services/networking/nat.nix
@@ -7,12 +7,14 @@
 with lib;
 
 let
-
   cfg = config.networking.nat;
 
   dest = if cfg.externalIP == null then "-j MASQUERADE" else "-j SNAT --to-source ${cfg.externalIP}";
 
+  helpers = import ./helpers.nix { inherit config lib; };
+
   flushNat = ''
+    ${helpers}
     ip46tables -w -t nat -D PREROUTING -j nixos-nat-pre 2>/dev/null|| true
     ip46tables -w -t nat -F nixos-nat-pre 2>/dev/null || true
     ip46tables -w -t nat -X nixos-nat-pre 2>/dev/null || true
@@ -27,6 +29,7 @@ let
   '';
 
   setupNat = ''
+    ${helpers}
     # Create subchain where we store rules
     ip46tables -w -t nat -N nixos-nat-pre
     ip46tables -w -t nat -N nixos-nat-post
diff --git a/nixos/modules/services/networking/unbound.nix b/nixos/modules/services/networking/unbound.nix
index 3cf82e8839bb..baed83591e1e 100644
--- a/nixos/modules/services/networking/unbound.nix
+++ b/nixos/modules/services/networking/unbound.nix
@@ -53,6 +53,13 @@ in
 
       enable = mkEnableOption "Unbound domain name server";
 
+      package = mkOption {
+        type = types.package;
+        default = pkgs.unbound;
+        defaultText = "pkgs.unbound";
+        description = "The unbound package to use";
+      };
+
       allowedAccess = mkOption {
         default = [ "127.0.0.0/24" ];
         type = types.listOf types.str;
@@ -94,7 +101,7 @@ in
 
   config = mkIf cfg.enable {
 
-    environment.systemPackages = [ pkgs.unbound ];
+    environment.systemPackages = [ cfg.package ];
 
     users.users.unbound = {
       description = "unbound daemon user";
@@ -114,7 +121,7 @@ in
         mkdir -m 0755 -p ${stateDir}/dev/
         cp ${confFile} ${stateDir}/unbound.conf
         ${optionalString cfg.enableRootTrustAnchor ''
-          ${pkgs.unbound}/bin/unbound-anchor -a ${rootTrustAnchorFile} || echo "Root anchor updated!"
+          ${cfg.package}/bin/unbound-anchor -a ${rootTrustAnchorFile} || echo "Root anchor updated!"
           chown unbound ${stateDir} ${rootTrustAnchorFile}
         ''}
         touch ${stateDir}/dev/random
@@ -122,7 +129,7 @@ in
       '';
 
       serviceConfig = {
-        ExecStart = "${pkgs.unbound}/bin/unbound -d -c ${stateDir}/unbound.conf";
+        ExecStart = "${cfg.package}/bin/unbound -d -c ${stateDir}/unbound.conf";
         ExecStopPost="${pkgs.utillinux}/bin/umount ${stateDir}/dev/random";
 
         ProtectSystem = true;
diff --git a/nixos/modules/services/web-servers/nginx/default.nix b/nixos/modules/services/web-servers/nginx/default.nix
index eb90dae94dfe..9b476ba7f1e5 100644
--- a/nixos/modules/services/web-servers/nginx/default.nix
+++ b/nixos/modules/services/web-servers/nginx/default.nix
@@ -47,7 +47,7 @@ let
   ''));
 
   configFile = pkgs.writers.writeNginxConfig "nginx.conf" ''
-    user ${cfg.user} ${cfg.group};
+    pid /run/nginx/nginx.pid;
     error_log ${cfg.logError};
     daemon off;
 
@@ -366,12 +366,7 @@ in
 
       preStart =  mkOption {
         type = types.lines;
-        default = ''
-          test -d ${cfg.stateDir}/logs || mkdir -m 750 -p ${cfg.stateDir}/logs
-          test `stat -c %a ${cfg.stateDir}` = "750" || chmod 750 ${cfg.stateDir}
-          test `stat -c %a ${cfg.stateDir}/logs` = "750" || chmod 750 ${cfg.stateDir}/logs
-          chown -R ${cfg.user}:${cfg.group} ${cfg.stateDir}
-        '';
+        default = "";
         description = "
           Shell commands executed before the service's nginx is started.
         ";
@@ -673,23 +668,35 @@ in
       }
     ];
 
+    systemd.tmpfiles.rules = [
+      "d '${cfg.stateDir}' 0750 ${cfg.user} ${cfg.group} - -"
+      "d '${cfg.stateDir}/logs' 0750 ${cfg.user} ${cfg.group} - -"
+    ];
+
     systemd.services.nginx = {
       description = "Nginx Web Server";
       wantedBy = [ "multi-user.target" ];
       wants = concatLists (map (vhostConfig: ["acme-${vhostConfig.serverName}.service" "acme-selfsigned-${vhostConfig.serverName}.service"]) acmeEnabledVhosts);
       after = [ "network.target" ] ++ map (vhostConfig: "acme-selfsigned-${vhostConfig.serverName}.service") acmeEnabledVhosts;
       stopIfChanged = false;
-      preStart =
-        ''
+      preStart = ''
         ${cfg.preStart}
-        ${cfg.package}/bin/nginx -c ${configPath} -p ${cfg.stateDir} -t
-        '';
+        ${cfg.package}/bin/nginx -c '${configPath}' -p '${cfg.stateDir}' -t
+      '';
       serviceConfig = {
-        ExecStart = "${cfg.package}/bin/nginx -c ${configPath} -p ${cfg.stateDir}";
+        ExecStart = "${cfg.package}/bin/nginx -c '${configPath}' -p '${cfg.stateDir}'";
         ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
         Restart = "always";
         RestartSec = "10s";
         StartLimitInterval = "1min";
+        # User and group
+        User = cfg.user;
+        Group = cfg.group;
+        # Runtime directory and mode
+        RuntimeDirectory = "nginx";
+        RuntimeDirectoryMode = "0750";
+        # Capabilities
+        AmbientCapabilities = [ "CAP_NET_BIND_SERVICE" "CAP_SYS_RESOURCE" ];
       };
     };
 
diff --git a/nixos/modules/services/web-servers/nginx/location-options.nix b/nixos/modules/services/web-servers/nginx/location-options.nix
index 2b3749d8a744..3d9e391ecf20 100644
--- a/nixos/modules/services/web-servers/nginx/location-options.nix
+++ b/nixos/modules/services/web-servers/nginx/location-options.nix
@@ -67,7 +67,7 @@ with lib;
     return = mkOption {
       type = types.nullOr types.str;
       default = null;
-      example = "301 http://example.com$request_uri;";
+      example = "301 http://example.com$request_uri";
       description = ''
         Adds a return directive, for e.g. redirections.
       '';
diff --git a/nixos/modules/services/web-servers/unit/default.nix b/nixos/modules/services/web-servers/unit/default.nix
index 32f6d475b34e..b07212580a55 100644
--- a/nixos/modules/services/web-servers/unit/default.nix
+++ b/nixos/modules/services/web-servers/unit/default.nix
@@ -85,7 +85,7 @@ in {
     systemd.tmpfiles.rules = [
       "d '${cfg.stateDir}' 0750 ${cfg.user} ${cfg.group} - -"
       "d '${cfg.logDir}' 0750 ${cfg.user} ${cfg.group} - -"
-     ];
+    ];
 
     systemd.services.unit = {
       description = "Unit App Server";
@@ -93,23 +93,39 @@ in {
       wantedBy = [ "multi-user.target" ];
       path = with pkgs; [ curl ];
       preStart = ''
-        test -f '/run/unit/control.unit.sock' || rm -f '/run/unit/control.unit.sock'
+        test -f '${cfg.stateDir}/conf.json' || rm -f '${cfg.stateDir}/conf.json'
       '';
       postStart = ''
         curl -X PUT --data-binary '@${configFile}' --unix-socket '/run/unit/control.unit.sock' 'http://localhost/config'
       '';
       serviceConfig = {
-        User = cfg.user;
-        Group = cfg.group;
-        AmbientCapabilities = "CAP_NET_BIND_SERVICE CAP_SETGID CAP_SETUID";
-        CapabilityBoundingSet = "CAP_NET_BIND_SERVICE CAP_SETGID CAP_SETUID";
         ExecStart = ''
           ${cfg.package}/bin/unitd --control 'unix:/run/unit/control.unit.sock' --pid '/run/unit/unit.pid' \
                                    --log '${cfg.logDir}/unit.log' --state '${cfg.stateDir}' --no-daemon \
                                    --user ${cfg.user} --group ${cfg.group}
         '';
+        # User and group
+        User = cfg.user;
+        Group = cfg.group;
+        # Capabilities
+        AmbientCapabilities = [ "CAP_NET_BIND_SERVICE" "CAP_SETGID" "CAP_SETUID" ];
+        # Security
+        NoNewPrivileges = true;
+        # Sanboxing
+        ProtectSystem = "full";
+        ProtectHome = true;
         RuntimeDirectory = "unit";
         RuntimeDirectoryMode = "0750";
+        PrivateTmp = true;
+        PrivateDevices = true;
+        ProtectHostname = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        RestrictRealtime = true;
+        PrivateMounts = true;
       };
     };
 
diff --git a/nixos/modules/services/x11/desktop-managers/cde.nix b/nixos/modules/services/x11/desktop-managers/cde.nix
new file mode 100644
index 000000000000..c1b6d3bf064a
--- /dev/null
+++ b/nixos/modules/services/x11/desktop-managers/cde.nix
@@ -0,0 +1,55 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  xcfg = config.services.xserver;
+  cfg = xcfg.desktopManager.cde;
+in {
+  options.services.xserver.desktopManager.cde = {
+    enable = mkEnableOption "Common Desktop Environment";
+  };
+
+  config = mkIf (xcfg.enable && cfg.enable) {
+    services.rpcbind.enable = true;
+
+    services.xinetd.enable = true;
+    services.xinetd.services = [
+      {
+        name = "cmsd";
+        protocol = "udp";
+        user = "root";
+        server = "${pkgs.cdesktopenv}/opt/dt/bin/rpc.cmsd";
+        extraConfig = ''
+          type  = RPC UNLISTED
+          rpc_number  = 100068
+          rpc_version = 2-5
+          only_from   = 127.0.0.1/0
+        '';
+      }
+    ];
+
+    users.groups.mail = {};
+    security.wrappers = {
+      dtmail = {
+        source = "${pkgs.cdesktopenv}/bin/dtmail";
+        group = "mail";
+        setgid = true;
+      };
+    };
+
+    system.activationScripts.setup-cde = ''
+      mkdir -p /var/dt/{tmp,appconfig/appmanager}
+      chmod a+w+t /var/dt/{tmp,appconfig/appmanager}
+    '';
+
+    services.xserver.desktopManager.session = [
+    { name = "CDE";
+      start = ''
+        exec ${pkgs.cdesktopenv}/opt/dt/bin/Xsession
+      '';
+    }];
+  };
+
+  meta.maintainers = [ maintainers.gnidorah ];
+}
diff --git a/nixos/modules/services/x11/desktop-managers/default.nix b/nixos/modules/services/x11/desktop-managers/default.nix
index 671a959cdde1..970fa620c6b6 100644
--- a/nixos/modules/services/x11/desktop-managers/default.nix
+++ b/nixos/modules/services/x11/desktop-managers/default.nix
@@ -20,7 +20,7 @@ in
   imports = [
     ./none.nix ./xterm.nix ./xfce.nix ./plasma5.nix ./lumina.nix
     ./lxqt.nix ./enlightenment.nix ./gnome3.nix ./kodi.nix ./maxx.nix
-    ./mate.nix ./pantheon.nix ./surf-display.nix
+    ./mate.nix ./pantheon.nix ./surf-display.nix ./cde.nix
   ];
 
   options = {
@@ -86,23 +86,14 @@ in
       };
 
       default = mkOption {
-        type = types.str;
-        default = "";
+        type = types.nullOr types.str;
+        default = null;
         example = "none";
-        description = "Default desktop manager loaded if none have been chosen.";
-        apply = defaultDM:
-          if defaultDM == "" && cfg.session.list != [] then
-            (head cfg.session.list).name
-          else if any (w: w.name == defaultDM) cfg.session.list then
-            defaultDM
-          else
-            builtins.trace ''
-              Default desktop manager (${defaultDM}) not found at evaluation time.
-              These are the known valid session names:
-                ${concatMapStringsSep "\n  " (w: "services.xserver.desktopManager.default = \"${w.name}\";") cfg.session.list}
-              It's also possible the default can be found in one of these packages:
-                ${concatMapStringsSep "\n  " (p: p.name) config.services.xserver.displayManager.extraSessionFilePackages}
-            '' defaultDM;
+        description = ''
+          <emphasis role="strong">Deprecated</emphasis>, please use <xref linkend="opt-services.xserver.displayManager.defaultSession"/> instead.
+
+          Default desktop manager loaded if none have been chosen.
+        '';
       };
 
     };
diff --git a/nixos/modules/services/x11/desktop-managers/gnome3.nix b/nixos/modules/services/x11/desktop-managers/gnome3.nix
index 6725595e1cfd..6d9bd284bc72 100644
--- a/nixos/modules/services/x11/desktop-managers/gnome3.nix
+++ b/nixos/modules/services/x11/desktop-managers/gnome3.nix
@@ -144,7 +144,7 @@ in
       services.gnome3.core-shell.enable = true;
       services.gnome3.core-utilities.enable = mkDefault true;
 
-      services.xserver.displayManager.extraSessionFilePackages = [ pkgs.gnome3.gnome-session ];
+      services.xserver.displayManager.sessionPackages = [ pkgs.gnome3.gnome-session ];
 
       environment.extraInit = ''
         ${concatMapStrings (p: ''
@@ -171,7 +171,7 @@ in
     })
 
     (mkIf flashbackEnabled {
-      services.xserver.displayManager.extraSessionFilePackages =  map
+      services.xserver.displayManager.sessionPackages =  map
         (wm: pkgs.gnome3.gnome-flashback.mkSessionForWm {
           inherit (wm) wmName wmLabel wmCommand;
         }) (optional cfg.flashback.enableMetacity {
diff --git a/nixos/modules/services/x11/desktop-managers/pantheon.nix b/nixos/modules/services/x11/desktop-managers/pantheon.nix
index 99db5b17b649..e07d5b5eaad7 100644
--- a/nixos/modules/services/x11/desktop-managers/pantheon.nix
+++ b/nixos/modules/services/x11/desktop-managers/pantheon.nix
@@ -69,7 +69,7 @@ in
 
   config = mkIf cfg.enable {
 
-    services.xserver.displayManager.extraSessionFilePackages = [ pkgs.pantheon.elementary-session-settings ];
+    services.xserver.displayManager.sessionPackages = [ pkgs.pantheon.elementary-session-settings ];
 
     # Ensure lightdm is used when Pantheon is enabled
     # Without it screen locking will be nonfunctional because of the use of lightlocker
@@ -81,9 +81,9 @@ in
 
     services.xserver.displayManager.lightdm.greeters.pantheon.enable = mkDefault true;
 
-    # If not set manually Pantheon session cannot be started
-    # Known issue of https://github.com/NixOS/nixpkgs/pull/43992
-    services.xserver.desktopManager.default = mkForce "pantheon";
+    # Without this, Elementary LightDM greeter will pre-select non-existent `default` session
+    # https://github.com/elementary/greeter/issues/368
+    services.xserver.displayManager.defaultSession = "pantheon";
 
     services.xserver.displayManager.sessionCommands = ''
       if test "$XDG_CURRENT_DESKTOP" = "Pantheon"; then
diff --git a/nixos/modules/services/x11/desktop-managers/surf-display.nix b/nixos/modules/services/x11/desktop-managers/surf-display.nix
index 140dde828daa..9aeb0bbd2a88 100644
--- a/nixos/modules/services/x11/desktop-managers/surf-display.nix
+++ b/nixos/modules/services/x11/desktop-managers/surf-display.nix
@@ -118,7 +118,7 @@ in {
   };
 
   config = mkIf cfg.enable {
-    services.xserver.displayManager.extraSessionFilePackages = [
+    services.xserver.displayManager.sessionPackages = [
       pkgs.surf-display
     ];
 
diff --git a/nixos/modules/services/x11/display-managers/account-service-util.nix b/nixos/modules/services/x11/display-managers/account-service-util.nix
new file mode 100644
index 000000000000..1dbe703b5662
--- /dev/null
+++ b/nixos/modules/services/x11/display-managers/account-service-util.nix
@@ -0,0 +1,39 @@
+{ accountsservice
+, glib
+, gobject-introspection
+, python3
+, wrapGAppsHook
+}:
+
+python3.pkgs.buildPythonApplication {
+  name = "set-session";
+
+  format = "other";
+
+  src = ./set-session.py;
+
+  dontUnpack = true;
+
+  strictDeps = false;
+
+  nativeBuildInputs = [
+    wrapGAppsHook
+    gobject-introspection
+  ];
+
+  buildInputs = [
+    accountsservice
+    glib
+  ];
+
+  propagatedBuildInputs = with python3.pkgs; [
+    pygobject3
+    ordered-set
+  ];
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp $src $out/bin/set-session
+    chmod +x $out/bin/set-session
+  '';
+}
diff --git a/nixos/modules/services/x11/display-managers/default.nix b/nixos/modules/services/x11/display-managers/default.nix
index c252c3c90c94..2d809b5cc9fd 100644
--- a/nixos/modules/services/x11/display-managers/default.nix
+++ b/nixos/modules/services/x11/display-managers/default.nix
@@ -27,16 +27,7 @@ let
     Xft.hintstyle: hintslight
   '';
 
-  mkCases = session:
-    concatStrings (
-      mapAttrsToList (name: starts: ''
-                       (${name})
-                         ${concatMapStringsSep "\n  " (n: n.start) starts}
-                         ;;
-                     '') (lib.groupBy (n: n.name) session)
-    );
-
-  # file provided by services.xserver.displayManager.session.wrapper
+  # file provided by services.xserver.displayManager.sessionData.wrapper
   xsessionWrapper = pkgs.writeScript "xsession-wrapper"
     ''
       #! ${pkgs.bash}/bin/bash
@@ -116,94 +107,44 @@ let
           # Run the supplied session command. Remove any double quotes with eval.
           eval exec "$@"
       else
-          # Fall back to the default window/desktopManager
-          exec ${cfg.displayManager.session.script}
+          # TODO: Do we need this? Should not the session always exist?
+          echo "error: unknown session $1" 1>&2
+          exit 1
       fi
     '';
 
-  # file provided by services.xserver.displayManager.session.script
-  xsession = wm: dm: pkgs.writeScript "xsession"
-    ''
-      #! ${pkgs.bash}/bin/bash
-
-      # Legacy session script used to construct .desktop files from
-      # `services.xserver.displayManager.session` entries. Called from
-      # `sessionWrapper`.
-
-      # Expected parameters:
-      #   $1 = <desktop-manager>+<window-manager>
-
-      # The first argument of this script is the session type.
-      sessionType="$1"
-      if [ "$sessionType" = default ]; then sessionType=""; fi
-
-      # The session type is "<desktop-manager>+<window-manager>", so
-      # extract those (see:
-      # http://wiki.bash-hackers.org/syntax/pe#substring_removal).
-      windowManager="''${sessionType##*+}"
-      : ''${windowManager:=${cfg.windowManager.default}}
-      desktopManager="''${sessionType%%+*}"
-      : ''${desktopManager:=${cfg.desktopManager.default}}
-
-      # Start the window manager.
-      case "$windowManager" in
-        ${mkCases wm}
-        (*) echo "$0: Window manager '$windowManager' not found.";;
-      esac
-
-      # Start the desktop manager.
-      case "$desktopManager" in
-        ${mkCases dm}
-        (*) echo "$0: Desktop manager '$desktopManager' not found.";;
-      esac
-
-      ${optionalString cfg.updateDbusEnvironment ''
-        ${lib.getBin pkgs.dbus}/bin/dbus-update-activation-environment --systemd --all
-      ''}
-
-      test -n "$waitPID" && wait "$waitPID"
-
-      ${config.systemd.package}/bin/systemctl --user stop graphical-session.target
-
-      exit 0
-    '';
-
-  # Desktop Entry Specification:
-  # - https://standards.freedesktop.org/desktop-entry-spec/latest/
-  # - https://standards.freedesktop.org/desktop-entry-spec/latest/ar01s06.html
-  mkDesktops = names: pkgs.runCommand "desktops"
+  installedSessions = pkgs.runCommand "desktops"
     { # trivial derivation
       preferLocalBuild = true;
       allowSubstitutes = false;
     }
     ''
-      mkdir -p "$out/share/xsessions"
-      ${concatMapStrings (n: ''
-        cat - > "$out/share/xsessions/${n}.desktop" << EODESKTOP
-        [Desktop Entry]
-        Version=1.0
-        Type=XSession
-        TryExec=${cfg.displayManager.session.script}
-        Exec=${cfg.displayManager.session.script} "${n}"
-        Name=${n}
-        Comment=
-        EODESKTOP
-      '') names}
+      mkdir -p "$out/share/"{xsessions,wayland-sessions}
 
       ${concatMapStrings (pkg: ''
+        for n in ${concatStringsSep " " pkg.providedSessions}; do
+          if ! test -f ${pkg}/share/wayland-sessions/$n.desktop -o \
+                    -f ${pkg}/share/xsessions/$n.desktop; then
+            echo "Couldn't find provided session name, $n.desktop, in session package ${pkg.name}:"
+            echo "  ${pkg}"
+            return 1
+          fi
+        done
+
         if test -d ${pkg}/share/xsessions; then
           ${xorg.lndir}/bin/lndir ${pkg}/share/xsessions $out/share/xsessions
         fi
-      '') cfg.displayManager.extraSessionFilePackages}
-
-      ${concatMapStrings (pkg: ''
         if test -d ${pkg}/share/wayland-sessions; then
-          mkdir -p "$out/share/wayland-sessions"
           ${xorg.lndir}/bin/lndir ${pkg}/share/wayland-sessions $out/share/wayland-sessions
         fi
-      '') cfg.displayManager.extraSessionFilePackages}
+      '') cfg.displayManager.sessionPackages}
     '';
 
+  dmDefault = cfg.desktopManager.default;
+  wmDefault = cfg.windowManager.default;
+
+  defaultSessionFromLegacyOptions = concatStringsSep "+" (filter (s: s != null) ([ dmDefault ] ++ optional (wmDefault != "none") wmDefault));
+
 in
 
 {
@@ -261,11 +202,24 @@ in
         '';
       };
 
-      extraSessionFilePackages = mkOption {
-        type = types.listOf types.package;
+      sessionPackages = mkOption {
+        type = with types; listOf (package // {
+          description = "package with provided sessions";
+          check = p: assertMsg
+            (package.check p && p ? providedSessions
+            && p.providedSessions != [] && all isString p.providedSessions)
+            ''
+              Package, '${p.name}', did not specify any session names, as strings, in
+              'passthru.providedSessions'. This is required when used as a session package.
+
+              The session names can be looked up in:
+                ${p}/share/xsessions
+                ${p}/share/wayland-sessions
+           '';
+        });
         default = [];
         description = ''
-          A list of packages containing xsession files to be passed to the display manager.
+          A list of packages containing x11 or wayland session files to be passed to the display manager.
         '';
       };
 
@@ -296,18 +250,50 @@ in
           inside the display manager with the desktop manager name
           followed by the window manager name.
         '';
-        apply = list: rec {
-          wm = filter (s: s.manage == "window") list;
-          dm = filter (s: s.manage == "desktop") list;
-          names = flip concatMap dm
-            (d: map (w: d.name + optionalString (w.name != "none") ("+" + w.name))
-              (filter (w: d.name != "none" || w.name != "none") wm));
-          desktops = mkDesktops names;
-          script = xsession wm dm;
+      };
+
+      sessionData = mkOption {
+        description = "Data exported for display managers’ convenience";
+        internal = true;
+        default = {};
+        apply = val: {
           wrapper = xsessionWrapper;
+          desktops = installedSessions;
+          sessionNames = concatMap (p: p.providedSessions) cfg.displayManager.sessionPackages;
+          # We do not want to force users to set defaultSession when they have only single DE.
+          autologinSession =
+            if cfg.displayManager.defaultSession != null then
+              cfg.displayManager.defaultSession
+            else if cfg.displayManager.sessionData.sessionNames != [] then
+              head cfg.displayManager.sessionData.sessionNames
+            else
+              null;
         };
       };
 
+      defaultSession = mkOption {
+        type = with types; nullOr str // {
+          description = "session name";
+          check = d:
+            assertMsg (d != null -> (str.check d && elem d cfg.displayManager.sessionData.sessionNames)) ''
+                Default graphical session, '${d}', not found.
+                Valid names for 'services.xserver.displayManager.defaultSession' are:
+                  ${concatStringsSep "\n  " cfg.displayManager.sessionData.sessionNames}
+              '';
+        };
+        default =
+          if dmDefault != null || wmDefault != null then
+            defaultSessionFromLegacyOptions
+          else
+            null;
+        example = "gnome";
+        description = ''
+          Graphical session to pre-select in the session chooser (only effective for GDM and LightDM).
+
+          On GDM, LightDM and SDDM, it will also be used as a session for auto-login.
+        '';
+      };
+
       job = {
 
         preStart = mkOption {
@@ -356,6 +342,27 @@ in
   };
 
   config = {
+    assertions = [
+      {
+        assertion = cfg.desktopManager.default != null || cfg.windowManager.default != null -> cfg.displayManager.defaultSession == defaultSessionFromLegacyOptions;
+        message = "You cannot use both services.xserver.displayManager.defaultSession option and legacy options (services.xserver.desktopManager.default and services.xserver.windowManager.default).";
+      }
+    ];
+
+    warnings =
+      mkIf (dmDefault != null || wmDefault != null) [
+        ''
+          The following options are deprecated:
+            ${concatStringsSep "\n  " (map ({c, t}: t) (filter ({c, t}: c != null) [
+            { c = dmDefault; t = "- services.xserver.desktopManager.default"; }
+            { c = wmDefault; t = "- services.xserver.windowManager.default"; }
+            ]))}
+          Please use
+            services.xserver.displayManager.defaultSession = "${concatStringsSep "+" (filter (s: s != null) [ dmDefault wmDefault ])}";
+          instead.
+        ''
+      ];
+
     services.xserver.displayManager.xserverBin = "${xorg.xorgserver.out}/bin/X";
 
     systemd.user.targets.graphical-session = {
@@ -364,6 +371,67 @@ in
         StopWhenUnneeded = false;
       };
     };
+
+    # Create desktop files and scripts for starting sessions for WMs/DMs
+    # that do not have upstream session files (those defined using services.{display,desktop,window}Manager.session options).
+    services.xserver.displayManager.sessionPackages =
+      let
+        dms = filter (s: s.manage == "desktop") cfg.displayManager.session;
+        wms = filter (s: s.manage == "window") cfg.displayManager.session;
+
+        # Script responsible for starting the window manager and the desktop manager.
+        xsession = wm: dm: pkgs.writeScript "xsession" ''
+          #! ${pkgs.bash}/bin/bash
+
+          # Legacy session script used to construct .desktop files from
+          # `services.xserver.displayManager.session` entries. Called from
+          # `sessionWrapper`.
+
+          # Start the window manager.
+          ${wm.start}
+
+          # Start the desktop manager.
+          ${dm.start}
+
+          ${optionalString cfg.updateDbusEnvironment ''
+            ${lib.getBin pkgs.dbus}/bin/dbus-update-activation-environment --systemd --all
+          ''}
+
+          test -n "$waitPID" && wait "$waitPID"
+
+          ${config.systemd.package}/bin/systemctl --user stop graphical-session.target
+
+          exit 0
+        '';
+      in
+        # We will generate every possible pair of WM and DM.
+        concatLists (
+          crossLists
+            (dm: wm: let
+              sessionName = "${dm.name}${optionalString (wm.name != "none") ("+" + wm.name)}";
+              script = xsession dm wm;
+            in
+              optional (dm.name != "none" || wm.name != "none")
+                (pkgs.writeTextFile {
+                  name = "${sessionName}-xsession";
+                  destination = "/share/xsessions/${sessionName}.desktop";
+                  # Desktop Entry Specification:
+                  # - https://standards.freedesktop.org/desktop-entry-spec/latest/
+                  # - https://standards.freedesktop.org/desktop-entry-spec/latest/ar01s06.html
+                  text = ''
+                    [Desktop Entry]
+                    Version=1.0
+                    Type=XSession
+                    TryExec=${script}
+                    Exec=${script}
+                    Name=${sessionName}
+                  '';
+                } // {
+                  providedSessions = [ sessionName ];
+                })
+            )
+            [dms wms]
+          );
   };
 
   imports = [
@@ -371,6 +439,7 @@ in
      "The option is no longer necessary because all display managers have already delegated lid management to systemd.")
     (mkRenamedOptionModule [ "services" "xserver" "displayManager" "job" "logsXsession" ] [ "services" "xserver" "displayManager" "job" "logToFile" ])
     (mkRenamedOptionModule [ "services" "xserver" "displayManager" "logToJournal" ] [ "services" "xserver" "displayManager" "job" "logToJournal" ])
+    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "extraSessionFilesPackages" ] [ "services" "xserver" "displayManager" "sessionPackages" ])
   ];
 
 }
diff --git a/nixos/modules/services/x11/display-managers/gdm.nix b/nixos/modules/services/x11/display-managers/gdm.nix
index 095569fa08aa..6630f012f04f 100644
--- a/nixos/modules/services/x11/display-managers/gdm.nix
+++ b/nixos/modules/services/x11/display-managers/gdm.nix
@@ -31,44 +31,9 @@ let
     load-module module-position-event-sounds
   '';
 
-  dmDefault = config.services.xserver.desktopManager.default;
-  wmDefault = config.services.xserver.windowManager.default;
-  hasDefaultUserSession = dmDefault != "none" || wmDefault != "none";
-  defaultSessionName = dmDefault + optionalString (wmDefault != "none") ("+" + wmDefault);
-
-  setSessionScript = pkgs.python3.pkgs.buildPythonApplication {
-    name = "set-session";
-
-    format = "other";
-
-    src = ./set-session.py;
-
-    dontUnpack = true;
-
-    strictDeps = false;
-
-    nativeBuildInputs = with pkgs; [
-      wrapGAppsHook
-      gobject-introspection
-    ];
-
-    buildInputs = with pkgs; [
-      accountsservice
-      glib
-    ];
-
-    propagatedBuildInputs = with pkgs.python3.pkgs; [
-      pygobject3
-      ordered-set
-    ];
-
-    installPhase = ''
-      mkdir -p $out/bin
-      cp $src $out/bin/set-session
-      chmod +x $out/bin/set-session
-    '';
-  };
+  defaultSessionName = config.services.xserver.displayManager.defaultSession;
 
+  setSessionScript = pkgs.callPackage ./account-service-util.nix { };
 in
 
 {
@@ -186,7 +151,7 @@ in
         environment = {
           GDM_X_SERVER_EXTRA_ARGS = toString
             (filter (arg: arg != "-terminate") cfg.xserverArgs);
-          XDG_DATA_DIRS = "${cfg.session.desktops}/share/";
+          XDG_DATA_DIRS = "${cfg.sessionData.desktops}/share/";
         } // optionalAttrs (xSessionWrapper != null) {
           # Make GDM use this wrapper before running the session, which runs the
           # configured setupCommands. This relies on a patched GDM which supports
@@ -204,16 +169,19 @@ in
           cat - > /run/gdm/.config/gnome-initial-setup-done <<- EOF
           yes
           EOF
-        ''
-        # TODO: Make setSessionScript aware of previously used sessions
-        # + optionalString hasDefaultUserSession ''
-        #   ${setSessionScript}/bin/set-session ${defaultSessionName}
-        # ''
-        ;
+        '' + optionalString (defaultSessionName != null) ''
+          # Set default session in session chooser to a specified values – basically ignore session history.
+          ${setSessionScript}/bin/set-session ${cfg.sessionData.autologinSession}
+        '';
       };
 
-    # Because sd_login_monitor_new requires /run/systemd/machines
-    systemd.services.display-manager.wants = [ "systemd-machined.service" ];
+    systemd.services.display-manager.wants = [
+      # Because sd_login_monitor_new requires /run/systemd/machines
+      "systemd-machined.service"
+      # setSessionScript wants AccountsService
+      "accounts-daemon.service"
+    ];
+
     systemd.services.display-manager.after = [
       "rc-local.service"
       "systemd-machined.service"
@@ -329,7 +297,7 @@ in
       ${optionalString cfg.gdm.debug "Enable=true"}
     '';
 
-    environment.etc."gdm/Xsession".source = config.services.xserver.displayManager.session.wrapper;
+    environment.etc."gdm/Xsession".source = config.services.xserver.displayManager.sessionData.wrapper;
 
     # GDM LFS PAM modules, adapted somehow to NixOS
     security.pam.services = {
diff --git a/nixos/modules/services/x11/display-managers/lightdm-greeters/mini.nix b/nixos/modules/services/x11/display-managers/lightdm-greeters/mini.nix
index fa9445af32e7..0025f9b36037 100644
--- a/nixos/modules/services/x11/display-managers/lightdm-greeters/mini.nix
+++ b/nixos/modules/services/x11/display-managers/lightdm-greeters/mini.nix
@@ -53,9 +53,8 @@ in
           Whether to enable lightdm-mini-greeter as the lightdm greeter.
 
           Note that this greeter starts only the default X session.
-          You can configure the default X session by
-          <option>services.xserver.desktopManager.default</option> and
-          <option>services.xserver.windowManager.default</option>.
+          You can configure the default X session using
+          <xref linkend="opt-services.xserver.displayManager.defaultSession"/>.
         '';
       };
 
diff --git a/nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix b/nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix
index 29cb6ccbc06b..77c94114e6d9 100644
--- a/nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix
+++ b/nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix
@@ -35,6 +35,9 @@ in
       name = "io.elementary.greeter";
     };
 
+    # Show manual login card.
+    services.xserver.displayManager.lightdm.extraSeatDefaults = "greeter-show-manual-login=true";
+
     environment.etc."lightdm/io.elementary.greeter.conf".source = "${pkgs.pantheon.elementary-greeter}/etc/lightdm/io.elementary.greeter.conf";
     environment.etc."wingpanel.d/io.elementary.greeter.whitelist".source = "${pkgs.pantheon.elementary-default-settings}/etc/wingpanel.d/io.elementary.greeter.whitelist";
 
diff --git a/nixos/modules/services/x11/display-managers/lightdm.nix b/nixos/modules/services/x11/display-managers/lightdm.nix
index cf4c05acbccd..f7face0adb7e 100644
--- a/nixos/modules/services/x11/display-managers/lightdm.nix
+++ b/nixos/modules/services/x11/display-managers/lightdm.nix
@@ -8,10 +8,9 @@ let
   dmcfg = xcfg.displayManager;
   xEnv = config.systemd.services.display-manager.environment;
   cfg = dmcfg.lightdm;
+  sessionData = dmcfg.sessionData;
 
-  dmDefault = xcfg.desktopManager.default;
-  wmDefault = xcfg.windowManager.default;
-  hasDefaultUserSession = dmDefault != "none" || wmDefault != "none";
+  setSessionScript = pkgs.callPackage ./account-service-util.nix { };
 
   inherit (pkgs) lightdm writeScript writeText;
 
@@ -45,22 +44,19 @@ let
         greeter-user = ${config.users.users.lightdm.name}
         greeters-directory = ${cfg.greeter.package}
       ''}
-      sessions-directory = ${dmcfg.session.desktops}/share/xsessions
+      sessions-directory = ${dmcfg.sessionData.desktops}/share/xsessions:${dmcfg.sessionData.desktops}/share/wayland-sessions
       ${cfg.extraConfig}
 
       [Seat:*]
       xserver-command = ${xserverWrapper}
-      session-wrapper = ${dmcfg.session.wrapper}
+      session-wrapper = ${dmcfg.sessionData.wrapper}
       ${optionalString cfg.greeter.enable ''
         greeter-session = ${cfg.greeter.name}
       ''}
       ${optionalString cfg.autoLogin.enable ''
         autologin-user = ${cfg.autoLogin.user}
         autologin-user-timeout = ${toString cfg.autoLogin.timeout}
-        autologin-session = ${defaultSessionName}
-      ''}
-      ${optionalString hasDefaultUserSession ''
-        user-session=${defaultSessionName}
+        autologin-session = ${sessionData.autologinSession}
       ''}
       ${optionalString (dmcfg.setupCommands != "") ''
         display-setup-script=${pkgs.writeScript "lightdm-display-setup" ''
@@ -71,7 +67,6 @@ let
       ${cfg.extraSeatDefaults}
     '';
 
-  defaultSessionName = dmDefault + optionalString (wmDefault != "none") ("+" + wmDefault);
 in
 {
   # Note: the order in which lightdm greeter modules are imported
@@ -199,11 +194,9 @@ in
           LightDM auto-login requires services.xserver.displayManager.lightdm.autoLogin.user to be set
         '';
       }
-      { assertion = cfg.autoLogin.enable -> dmDefault != "none" || wmDefault != "none";
+      { assertion = cfg.autoLogin.enable -> sessionData.autologinSession != null;
         message = ''
-          LightDM auto-login requires that services.xserver.desktopManager.default and
-          services.xserver.windowManager.default are set to valid values. The current
-          default session: ${defaultSessionName} is not valid.
+          LightDM auto-login requires that services.xserver.displayManager.defaultSession is set.
         '';
       }
       { assertion = !cfg.greeter.enable -> (cfg.autoLogin.enable && cfg.autoLogin.timeout == 0);
@@ -214,6 +207,20 @@ in
       }
     ];
 
+    # Set default session in session chooser to a specified values – basically ignore session history.
+    # Auto-login is already covered by a config value.
+    services.xserver.displayManager.job.preStart = optionalString (!cfg.autoLogin.enable && dmcfg.defaultSession != null) ''
+      ${setSessionScript}/bin/set-session ${dmcfg.defaultSession}
+    '';
+
+    # setSessionScript needs session-files in XDG_DATA_DIRS
+    services.xserver.displayManager.job.environment.XDG_DATA_DIRS = "${dmcfg.sessionData.desktops}/share/";
+
+    # setSessionScript wants AccountsService
+    systemd.services.display-manager.wants = [
+      "accounts-daemon.service"
+    ];
+
     # lightdm relaunches itself via just `lightdm`, so needs to be on the PATH
     services.xserver.displayManager.job.execCmd = ''
       export PATH=${lightdm}/sbin:$PATH
diff --git a/nixos/modules/services/x11/display-managers/sddm.nix b/nixos/modules/services/x11/display-managers/sddm.nix
index 24e120c4f2cf..4224c557ed63 100644
--- a/nixos/modules/services/x11/display-managers/sddm.nix
+++ b/nixos/modules/services/x11/display-managers/sddm.nix
@@ -50,8 +50,8 @@ let
     MinimumVT=${toString (if xcfg.tty != null then xcfg.tty else 7)}
     ServerPath=${xserverWrapper}
     XephyrPath=${pkgs.xorg.xorgserver.out}/bin/Xephyr
-    SessionCommand=${dmcfg.session.wrapper}
-    SessionDir=${dmcfg.session.desktops}/share/xsessions
+    SessionCommand=${dmcfg.sessionData.wrapper}
+    SessionDir=${dmcfg.sessionData.desktops}/share/xsessions
     XauthPath=${pkgs.xorg.xauth}/bin/xauth
     DisplayCommand=${Xsetup}
     DisplayStopCommand=${Xstop}
@@ -59,23 +59,19 @@ let
 
     [Wayland]
     EnableHidpi=${if cfg.enableHidpi then "true" else "false"}
-    SessionDir=${dmcfg.session.desktops}/share/wayland-sessions
+    SessionDir=${dmcfg.sessionData.desktops}/share/wayland-sessions
 
     ${optionalString cfg.autoLogin.enable ''
     [Autologin]
     User=${cfg.autoLogin.user}
-    Session=${defaultSessionName}.desktop
+    Session=${autoLoginSessionName}.desktop
     Relogin=${boolToString cfg.autoLogin.relogin}
     ''}
 
     ${cfg.extraConfig}
   '';
 
-  defaultSessionName =
-    let
-      dm = xcfg.desktopManager.default;
-      wm = xcfg.windowManager.default;
-    in dm + optionalString (wm != "none") ("+" + wm);
+  autoLoginSessionName = dmcfg.sessionData.autologinSession;
 
 in
 {
@@ -210,11 +206,9 @@ in
           SDDM auto-login requires services.xserver.displayManager.sddm.autoLogin.user to be set
         '';
       }
-      { assertion = cfg.autoLogin.enable -> elem defaultSessionName dmcfg.session.names;
+      { assertion = cfg.autoLogin.enable -> autoLoginSessionName != null;
         message = ''
-          SDDM auto-login requires that services.xserver.desktopManager.default and
-          services.xserver.windowManager.default are set to valid values. The current
-          default session: ${defaultSessionName} is not valid.
+          SDDM auto-login requires that services.xserver.displayManager.defaultSession is set.
         '';
       }
     ];
diff --git a/nixos/modules/services/x11/imwheel.nix b/nixos/modules/services/x11/imwheel.nix
new file mode 100644
index 000000000000..3923df498e79
--- /dev/null
+++ b/nixos/modules/services/x11/imwheel.nix
@@ -0,0 +1,68 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+  cfg = config.services.xserver.imwheel;
+in
+  {
+    options = {
+      services.xserver.imwheel = {
+        enable = mkEnableOption "IMWheel service";
+
+        extraOptions = mkOption {
+          type = types.listOf types.str;
+          default = [ "--buttons=45" ];
+          example = [ "--debug" ];
+          description = ''
+            Additional command-line arguments to pass to
+            <command>imwheel</command>.
+          '';
+        };
+
+        rules = mkOption {
+          type = types.attrsOf types.str;
+          default = {};
+          example = literalExample ''
+            ".*" = '''
+              None,      Up,   Button4, 8
+              None,      Down, Button5, 8
+              Shift_L,   Up,   Shift_L|Button4, 4
+              Shift_L,   Down, Shift_L|Button5, 4
+              Control_L, Up,   Control_L|Button4
+              Control_L, Down, Control_L|Button5
+            ''';
+          '';
+          description = ''
+            Window class translation rules.
+            /etc/X11/imwheelrc is generated based on this config
+            which means this config is global for all users.
+            See <link xlink:href="http://imwheel.sourceforge.net/imwheel.1.html">offical man pages</link>
+            for more informations.
+          '';
+        };
+      };
+    };
+
+    config = mkIf cfg.enable {
+      environment.systemPackages = [ pkgs.imwheel ];
+
+      environment.etc."X11/imwheel/imwheelrc".source =
+        pkgs.writeText "imwheelrc" (concatStringsSep "\n\n"
+          (mapAttrsToList
+            (rule: conf: "\"${rule}\"\n${conf}") cfg.rules
+          ));
+
+      systemd.user.services.imwheel = {
+        description = "imwheel service";
+        wantedBy = [ "graphical-session.target" ];
+        partOf = [ "graphical-session.target" ];
+        serviceConfig = {
+          ExecStart = "${pkgs.imwheel}/bin/imwheel " + escapeShellArgs ([
+            "--detach"
+            "--kill"
+          ] ++ cfg.extraOptions);
+          ExecStop = "${pkgs.procps}/bin/pkill imwheel";
+          Restart = "on-failure";
+        };
+      };
+    };
+  }
diff --git a/nixos/modules/services/x11/window-managers/default.nix b/nixos/modules/services/x11/window-managers/default.nix
index c17f3830d0e9..04a9fc46628c 100644
--- a/nixos/modules/services/x11/window-managers/default.nix
+++ b/nixos/modules/services/x11/window-managers/default.nix
@@ -59,15 +59,14 @@ in
       };
 
       default = mkOption {
-        type = types.str;
-        default = "none";
+        type = types.nullOr types.str;
+        default = null;
         example = "wmii";
-        description = "Default window manager loaded if none have been chosen.";
-        apply = defaultWM:
-          if any (w: w.name == defaultWM) cfg.session then
-            defaultWM
-          else
-            throw "Default window manager (${defaultWM}) not found.";
+        description = ''
+          <emphasis role="strong">Deprecated</emphasis>, please use <xref linkend="opt-services.xserver.displayManager.defaultSession"/> instead.
+
+          Default window manager loaded if none have been chosen.
+        '';
       };
 
     };
diff --git a/nixos/modules/tasks/filesystems/nfs.nix b/nixos/modules/tasks/filesystems/nfs.nix
index e0e8bb1f03de..ddcc0ed8f5a4 100644
--- a/nixos/modules/tasks/filesystems/nfs.nix
+++ b/nixos/modules/tasks/filesystems/nfs.nix
@@ -25,6 +25,9 @@ let
   '';
 
   nfsConfFile = pkgs.writeText "nfs.conf" cfg.extraConfig;
+  requestKeyConfFile = pkgs.writeText "request-key.conf" ''
+    create id_resolver * * ${pkgs.nfs-utils}/bin/nfsidmap -t 600 %k %d
+  '';
 
   cfg = config.services.nfs;
 
@@ -57,9 +60,12 @@ in
 
     systemd.packages = [ pkgs.nfs-utils ];
 
+    environment.systemPackages = [ pkgs.keyutils ];
+
     environment.etc = {
       "idmapd.conf".source = idmapdConfFile;
       "nfs.conf".source = nfsConfFile;
+      "request-key.conf".source = requestKeyConfFile;
     };
 
     systemd.services.nfs-blkmap =
diff --git a/nixos/modules/tasks/kbd.nix b/nixos/modules/tasks/kbd.nix
deleted file mode 100644
index c6ba998b19e6..000000000000
--- a/nixos/modules/tasks/kbd.nix
+++ /dev/null
@@ -1,127 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-
-  makeColor = n: value: "COLOR_${toString n}=${value}";
-  makeColorCS =
-    let positions = [ "0" "1" "2" "3" "4" "5" "6" "7" "8" "9" "A" "B" "C" "D" "E" "F" ];
-    in n: value: "\\033]P${elemAt positions (n - 1)}${value}";
-  colors = concatImapStringsSep "\n" makeColor config.i18n.consoleColors;
-
-  isUnicode = hasSuffix "UTF-8" (toUpper config.i18n.defaultLocale);
-
-  optimizedKeymap = pkgs.runCommand "keymap" {
-    nativeBuildInputs = [ pkgs.buildPackages.kbd ];
-    LOADKEYS_KEYMAP_PATH = "${kbdEnv}/share/keymaps/**";
-    preferLocalBuild = true;
-  } ''
-    loadkeys -b ${optionalString isUnicode "-u"} "${config.i18n.consoleKeyMap}" > $out
-  '';
-
-  # Sadly, systemd-vconsole-setup doesn't support binary keymaps.
-  vconsoleConf = pkgs.writeText "vconsole.conf" ''
-    KEYMAP=${config.i18n.consoleKeyMap}
-    FONT=${config.i18n.consoleFont}
-    ${colors}
-  '';
-
-  kbdEnv = pkgs.buildEnv {
-    name = "kbd-env";
-    paths = [ pkgs.kbd ] ++ config.i18n.consolePackages;
-    pathsToLink = [ "/share/consolefonts" "/share/consoletrans" "/share/keymaps" "/share/unimaps" ];
-  };
-
-  setVconsole = !config.boot.isContainer;
-in
-
-{
-  ###### interface
-
-  options = {
-
-    # most options are defined in i18n.nix
-
-    # FIXME: still needed?
-    boot.extraTTYs = mkOption {
-      default = [];
-      type = types.listOf types.str;
-      example = ["tty8" "tty9"];
-      description = ''
-        Tty (virtual console) devices, in addition to the consoles on
-        which mingetty and syslogd run, that must be initialised.
-        Only useful if you have some program that you want to run on
-        some fixed console.  For example, the NixOS installation CD
-        opens the manual in a web browser on console 7, so it sets
-        <option>boot.extraTTYs</option> to <literal>["tty7"]</literal>.
-      '';
-    };
-
-    boot.earlyVconsoleSetup = mkOption {
-      default = false;
-      type = types.bool;
-      description = ''
-        Enable setting font as early as possible (in initrd).
-      '';
-    };
-
-  };
-
-
-  ###### implementation
-
-  config = mkMerge [
-    (mkIf (!setVconsole) {
-      systemd.services.systemd-vconsole-setup.enable = false;
-    })
-
-    (mkIf setVconsole (mkMerge [
-      { environment.systemPackages = [ pkgs.kbd ];
-
-        # Let systemd-vconsole-setup.service do the work of setting up the
-        # virtual consoles.
-        environment.etc."vconsole.conf".source = vconsoleConf;
-        # Provide kbd with additional packages.
-        environment.etc.kbd.source = "${kbdEnv}/share";
-
-        boot.initrd.preLVMCommands = mkBefore ''
-          kbd_mode ${if isUnicode then "-u" else "-a"} -C /dev/console
-          printf "\033%%${if isUnicode then "G" else "@"}" >> /dev/console
-          loadkmap < ${optimizedKeymap}
-
-          ${optionalString config.boot.earlyVconsoleSetup ''
-            setfont -C /dev/console $extraUtils/share/consolefonts/font.psf
-          ''}
-
-          ${concatImapStringsSep "\n" (n: color: ''
-            printf "${makeColorCS n color}" >> /dev/console
-          '') config.i18n.consoleColors}
-        '';
-
-        systemd.services.systemd-vconsole-setup =
-          { before = [ "display-manager.service" ];
-            after = [ "systemd-udev-settle.service" ];
-            restartTriggers = [ vconsoleConf kbdEnv ];
-          };
-      }
-
-      (mkIf config.boot.earlyVconsoleSetup {
-        boot.initrd.extraUtilsCommands = ''
-          mkdir -p $out/share/consolefonts
-          ${if substring 0 1 config.i18n.consoleFont == "/" then ''
-            font="${config.i18n.consoleFont}"
-          '' else ''
-            font="$(echo ${kbdEnv}/share/consolefonts/${config.i18n.consoleFont}.*)"
-          ''}
-          if [[ $font == *.gz ]]; then
-            gzip -cd $font > $out/share/consolefonts/font.psf
-          else
-            cp -L $font $out/share/consolefonts/font.psf
-          fi
-        '';
-      })
-    ]))
-  ];
-
-}
diff --git a/nixos/modules/tasks/network-interfaces-systemd.nix b/nixos/modules/tasks/network-interfaces-systemd.nix
index 9ffa1089ee69..e25dc0c0b39a 100644
--- a/nixos/modules/tasks/network-interfaces-systemd.nix
+++ b/nixos/modules/tasks/network-interfaces-systemd.nix
@@ -60,8 +60,8 @@ in
       let
         domains = cfg.search ++ (optional (cfg.domain != null) cfg.domain);
         genericNetwork = override:
-          let gateway = optional (cfg.defaultGateway != null) cfg.defaultGateway.address
-            ++ optional (cfg.defaultGateway6 != null) cfg.defaultGateway6.address;
+          let gateway = optional (cfg.defaultGateway != null && (cfg.defaultGateway.address or "") != "") cfg.defaultGateway.address
+            ++ optional (cfg.defaultGateway6 != null && (cfg.defaultGateway6.address or "") != "") cfg.defaultGateway6.address;
           in optionalAttrs (gateway != [ ]) {
             routes = override [
               {
diff --git a/nixos/modules/virtualisation/container-config.nix b/nixos/modules/virtualisation/container-config.nix
index f7a37d8c9f3b..6ff6bdd30c20 100644
--- a/nixos/modules/virtualisation/container-config.nix
+++ b/nixos/modules/virtualisation/container-config.nix
@@ -10,6 +10,7 @@ with lib;
     nix.optimise.automatic = mkDefault false; # the store is host managed
     services.udisks2.enable = mkDefault false;
     powerManagement.enable = mkDefault false;
+    documentation.nixos.enable = mkDefault false;
 
     networking.useHostResolvConf = mkDefault true;
 
diff --git a/nixos/modules/virtualisation/lxd.nix b/nixos/modules/virtualisation/lxd.nix
index 505c11abd208..b4934a86cf56 100644
--- a/nixos/modules/virtualisation/lxd.nix
+++ b/nixos/modules/virtualisation/lxd.nix
@@ -35,6 +35,18 @@ in
           with nixos.
         '';
       };
+      recommendedSysctlSettings = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          enables various settings to avoid common pitfalls when
+          running containers requiring many file operations.
+          Fixes errors like "Too many open files" or
+          "neighbour: ndisc_cache: neighbor table overflow!".
+          See https://lxd.readthedocs.io/en/latest/production-setup/
+          for details.
+        '';
+      };
     };
   };
 
@@ -69,8 +81,11 @@ in
         ExecStart = "@${pkgs.lxd.bin}/bin/lxd lxd --group lxd";
         Type = "simple";
         KillMode = "process"; # when stopping, leave the containers alone
+        LimitMEMLOCK = "infinity";
+        LimitNOFILE = "1048576";
+        LimitNPROC = "infinity";
+        TasksMax = "infinity";
       };
-
     };
 
     users.groups.lxd.gid = config.ids.gids.lxd;
@@ -79,5 +94,16 @@ in
       subUidRanges = [ { startUid = 1000000; count = 65536; } ];
       subGidRanges = [ { startGid = 1000000; count = 65536; } ];
     };
+
+    boot.kernel.sysctl = mkIf cfg.recommendedSysctlSettings {
+      "fs.inotify.max_queued_events" = 1048576;
+      "fs.inotify.max_user_instances" = 1048576;
+      "fs.inotify.max_user_watches" = 1048576;
+      "vm.max_map_count" = 262144;
+      "kernel.dmesg_restrict" = 1;
+      "net.ipv4.neigh.default.gc_thresh3" = 8192;
+      "net.ipv6.neigh.default.gc_thresh3" = 8192;
+      "kernel.keys.maxkeys" = 2000;
+    };
   };
 }
diff --git a/nixos/release-combined.nix b/nixos/release-combined.nix
index 678ce3c28800..ca9c6f9a7f91 100644
--- a/nixos/release-combined.nix
+++ b/nixos/release-combined.nix
@@ -120,8 +120,8 @@ in rec {
         (all nixos.tests.networking.scripted.macvlan)
         (all nixos.tests.networking.scripted.sit)
         (all nixos.tests.networking.scripted.vlan)
-        (all nixos.tests.nfs3)
-        (all nixos.tests.nfs4)
+        (all nixos.tests.nfs3.simple)
+        (all nixos.tests.nfs4.simple)
         (all nixos.tests.openssh)
         (all nixos.tests.php-pcre)
         (all nixos.tests.predictable-interface-names.predictable)
diff --git a/nixos/tests/3proxy.nix b/nixos/tests/3proxy.nix
new file mode 100644
index 000000000000..b8e1dac0e89e
--- /dev/null
+++ b/nixos/tests/3proxy.nix
@@ -0,0 +1,162 @@
+import ./make-test.nix ({ pkgs, ...} : {
+  name = "3proxy";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ misuzu ];
+  };
+
+  nodes = {
+    peer0 = { lib, ... }: {
+      networking.useDHCP = false;
+      networking.interfaces.eth1 = {
+        ipv4.addresses = [
+          {
+            address = "192.168.0.1";
+            prefixLength = 24;
+          }
+          {
+            address = "216.58.211.111";
+            prefixLength = 24;
+          }
+        ];
+      };
+    };
+
+    peer1 = { lib, ... }: {
+      networking.useDHCP = false;
+      networking.interfaces.eth1 = {
+        ipv4.addresses = [
+          {
+            address = "192.168.0.2";
+            prefixLength = 24;
+          }
+          {
+            address = "216.58.211.112";
+            prefixLength = 24;
+          }
+        ];
+      };
+      # test that binding to [::] is working when ipv6 is disabled
+      networking.enableIPv6 = false;
+      services._3proxy = {
+        enable = true;
+        services = [
+          {
+            type = "admin";
+            bindPort = 9999;
+            auth = [ "none" ];
+          }
+          {
+            type = "proxy";
+            bindPort = 3128;
+            auth = [ "none" ];
+          }
+        ];
+      };
+      networking.firewall.allowedTCPPorts = [ 3128 9999 ];
+    };
+
+    peer2 = { lib, ... }: {
+      networking.useDHCP = false;
+      networking.interfaces.eth1 = {
+        ipv4.addresses = [
+          {
+            address = "192.168.0.3";
+            prefixLength = 24;
+          }
+          {
+            address = "216.58.211.113";
+            prefixLength = 24;
+          }
+        ];
+      };
+      services._3proxy = {
+        enable = true;
+        services = [
+          {
+            type = "admin";
+            bindPort = 9999;
+            auth = [ "none" ];
+          }
+          {
+            type = "proxy";
+            bindPort = 3128;
+            auth = [ "iponly" ];
+            acl = [
+              {
+                rule = "allow";
+              }
+            ];
+          }
+        ];
+      };
+      networking.firewall.allowedTCPPorts = [ 3128 9999 ];
+    };
+
+    peer3 = { lib, ... }: {
+      networking.useDHCP = false;
+      networking.interfaces.eth1 = {
+        ipv4.addresses = [
+          {
+            address = "192.168.0.4";
+            prefixLength = 24;
+          }
+          {
+            address = "216.58.211.114";
+            prefixLength = 24;
+          }
+        ];
+      };
+      services._3proxy = {
+        enable = true;
+        usersFile = pkgs.writeText "3proxy.passwd" ''
+          admin:CR:$1$.GUV4Wvk$WnEVQtaqutD9.beO5ar1W/
+        '';
+        services = [
+          {
+            type = "admin";
+            bindPort = 9999;
+            auth = [ "none" ];
+          }
+          {
+            type = "proxy";
+            bindPort = 3128;
+            auth = [ "strong" ];
+            acl = [
+              {
+                rule = "allow";
+              }
+            ];
+          }
+        ];
+      };
+      networking.firewall.allowedTCPPorts = [ 3128 9999 ];
+    };
+  };
+
+  testScript = ''
+    startAll;
+
+    $peer1->waitForUnit("3proxy.service");
+
+    # test none auth
+    $peer0->succeed("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://192.168.0.2:3128 -S -O /dev/null http://216.58.211.112:9999");
+    $peer0->succeed("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://192.168.0.2:3128 -S -O /dev/null http://192.168.0.2:9999");
+    $peer0->succeed("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://192.168.0.2:3128 -S -O /dev/null http://127.0.0.1:9999");
+
+    $peer2->waitForUnit("3proxy.service");
+
+    # test iponly auth
+    $peer0->succeed("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://192.168.0.3:3128 -S -O /dev/null http://216.58.211.113:9999");
+    $peer0->fail("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://192.168.0.3:3128 -S -O /dev/null http://192.168.0.3:9999");
+    $peer0->fail("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://192.168.0.3:3128 -S -O /dev/null http://127.0.0.1:9999");
+
+    $peer3->waitForUnit("3proxy.service");
+
+    # test strong auth
+    $peer0->succeed("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://admin:bigsecret\@192.168.0.4:3128 -S -O /dev/null http://216.58.211.114:9999");
+    $peer0->fail("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://admin:bigsecret\@192.168.0.4:3128 -S -O /dev/null http://192.168.0.4:9999");
+    $peer0->fail("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://192.168.0.4:3128 -S -O /dev/null http://216.58.211.114:9999");
+    $peer0->fail("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://192.168.0.4:3128 -S -O /dev/null http://192.168.0.4:9999");
+    $peer0->fail("${pkgs.wget}/bin/wget -e use_proxy=yes -e http_proxy=http://192.168.0.4:3128 -S -O /dev/null http://127.0.0.1:9999");
+  '';
+})
diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 39ee3206d806..6413895c4c5e 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -21,6 +21,7 @@ let
     else {};
 in
 {
+  _3proxy = handleTest ./3proxy.nix {};
   acme = handleTestOn ["x86_64-linux"] ./acme.nix {};
   atd = handleTest ./atd.nix {};
   automysqlbackup = handleTest ./automysqlbackup.nix {};
@@ -190,8 +191,9 @@ in
   networkingProxy = handleTest ./networking-proxy.nix {};
   nextcloud = handleTest ./nextcloud {};
   nexus = handleTest ./nexus.nix {};
-  nfs3 = handleTest ./nfs.nix { version = 3; };
-  nfs4 = handleTest ./nfs.nix { version = 4; };
+  # TODO: Test nfsv3 + Kerberos
+  nfs3 = handleTest ./nfs { version = 3; };
+  nfs4 = handleTest ./nfs { version = 4; };
   nghttpx = handleTest ./nghttpx.nix {};
   nginx = handleTest ./nginx.nix {};
   nginx-sso = handleTest ./nginx-sso.nix {};
@@ -294,5 +296,6 @@ in
   xss-lock = handleTest ./xss-lock.nix {};
   yabar = handleTest ./yabar.nix {};
   yggdrasil = handleTest ./yggdrasil.nix {};
+  zsh-history = handleTest ./zsh-history.nix {};
   zookeeper = handleTest ./zookeeper.nix {};
 }
diff --git a/nixos/tests/common/x11.nix b/nixos/tests/common/x11.nix
index c5a7c165d126..5ad0ac20fac8 100644
--- a/nixos/tests/common/x11.nix
+++ b/nixos/tests/common/x11.nix
@@ -1,12 +1,12 @@
+{ lib, ... }:
+
 { services.xserver.enable = true;
 
   # Automatically log in.
   services.xserver.displayManager.auto.enable = true;
 
   # Use IceWM as the window manager.
-  services.xserver.windowManager.default = "icewm";
-  services.xserver.windowManager.icewm.enable = true;
-
   # Don't use a desktop manager.
-  services.xserver.desktopManager.default = "none";
+  services.xserver.displayManager.defaultSession = lib.mkDefault "none+icewm";
+  services.xserver.windowManager.icewm.enable = true;
 }
diff --git a/nixos/tests/gnome3-xorg.nix b/nixos/tests/gnome3-xorg.nix
index eb4c376319be..aa03501f6a55 100644
--- a/nixos/tests/gnome3-xorg.nix
+++ b/nixos/tests/gnome3-xorg.nix
@@ -16,7 +16,7 @@ import ./make-test.nix ({ pkgs, ...} : {
       services.xserver.displayManager.lightdm.autoLogin.enable = true;
       services.xserver.displayManager.lightdm.autoLogin.user = "alice";
       services.xserver.desktopManager.gnome3.enable = true;
-      services.xserver.desktopManager.default = "gnome-xorg";
+      services.xserver.displayManager.defaultSession = "gnome-xorg";
 
       virtualisation.memorySize = 1024;
     };
diff --git a/nixos/tests/hadoop/hdfs.nix b/nixos/tests/hadoop/hdfs.nix
index e7d72a56e1e7..85aaab34b158 100644
--- a/nixos/tests/hadoop/hdfs.nix
+++ b/nixos/tests/hadoop/hdfs.nix
@@ -1,4 +1,4 @@
-import ../make-test.nix ({...}: {
+import ../make-test-python.nix ({...}: {
   nodes = {
     namenode = {pkgs, ...}: {
       services.hadoop = {
@@ -35,20 +35,20 @@ import ../make-test.nix ({...}: {
   };
 
   testScript = ''
-    startAll
+    start_all()
 
-    $namenode->waitForUnit("hdfs-namenode");
-    $namenode->waitForUnit("network.target");
-    $namenode->waitForOpenPort(8020);
-    $namenode->waitForOpenPort(9870);
+    namenode.wait_for_unit("hdfs-namenode")
+    namenode.wait_for_unit("network.target")
+    namenode.wait_for_open_port(8020)
+    namenode.wait_for_open_port(9870)
 
-    $datanode->waitForUnit("hdfs-datanode");
-    $datanode->waitForUnit("network.target");
-    $datanode->waitForOpenPort(9864);
-    $datanode->waitForOpenPort(9866);
-    $datanode->waitForOpenPort(9867);
+    datanode.wait_for_unit("hdfs-datanode")
+    datanode.wait_for_unit("network.target")
+    datanode.wait_for_open_port(9864)
+    datanode.wait_for_open_port(9866)
+    datanode.wait_for_open_port(9867)
 
-    $namenode->succeed("curl http://namenode:9870");
-    $datanode->succeed("curl http://datanode:9864");
+    namenode.succeed("curl http://namenode:9870")
+    datanode.succeed("curl http://datanode:9864")
   '';
 })
diff --git a/nixos/tests/hadoop/yarn.nix b/nixos/tests/hadoop/yarn.nix
index 031592301f17..2264ecaff155 100644
--- a/nixos/tests/hadoop/yarn.nix
+++ b/nixos/tests/hadoop/yarn.nix
@@ -1,4 +1,4 @@
-import ../make-test.nix ({...}: {
+import ../make-test-python.nix ({...}: {
   nodes = {
     resourcemanager = {pkgs, ...}: {
       services.hadoop.package = pkgs.hadoop_3_1;
@@ -28,19 +28,19 @@ import ../make-test.nix ({...}: {
   };
 
   testScript = ''
-    startAll;
+    start_all()
 
-    $resourcemanager->waitForUnit("yarn-resourcemanager");
-    $resourcemanager->waitForUnit("network.target");
-    $resourcemanager->waitForOpenPort(8031);
-    $resourcemanager->waitForOpenPort(8088);
+    resourcemanager.wait_for_unit("yarn-resourcemanager")
+    resourcemanager.wait_for_unit("network.target")
+    resourcemanager.wait_for_open_port(8031)
+    resourcemanager.wait_for_open_port(8088)
 
-    $nodemanager->waitForUnit("yarn-nodemanager");
-    $nodemanager->waitForUnit("network.target");
-    $nodemanager->waitForOpenPort(8042);
-    $nodemanager->waitForOpenPort(8041);
+    nodemanager.wait_for_unit("yarn-nodemanager")
+    nodemanager.wait_for_unit("network.target")
+    nodemanager.wait_for_open_port(8042)
+    nodemanager.wait_for_open_port(8041)
 
-    $resourcemanager->succeed("curl http://localhost:8088");
-    $nodemanager->succeed("curl http://localhost:8042");
+    resourcemanager.succeed("curl http://localhost:8088")
+    nodemanager.succeed("curl http://localhost:8042")
   '';
 })
diff --git a/nixos/tests/haproxy.nix b/nixos/tests/haproxy.nix
index 72e77a68193e..b6fed3e2108f 100644
--- a/nixos/tests/haproxy.nix
+++ b/nixos/tests/haproxy.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ...}: {
+import ./make-test-python.nix ({ pkgs, ...}: {
   name = "haproxy";
   nodes = {
     machine = { ... }: {
@@ -33,11 +33,13 @@ import ./make-test.nix ({ pkgs, ...}: {
     };
   };
   testScript = ''
-    startAll;
-    $machine->waitForUnit('multi-user.target');
-    $machine->waitForUnit('haproxy.service');
-    $machine->waitForUnit('httpd.service');
-    $machine->succeed('curl -k http://localhost:80/index.txt | grep "We are all good!"');
-    $machine->succeed('curl -k http://localhost:80/metrics | grep haproxy_process_pool_allocated_bytes');
+    start_all()
+    machine.wait_for_unit("multi-user.target")
+    machine.wait_for_unit("haproxy.service")
+    machine.wait_for_unit("httpd.service")
+    assert "We are all good!" in machine.succeed("curl -k http://localhost:80/index.txt")
+    assert "haproxy_process_pool_allocated_bytes" in machine.succeed(
+        "curl -k http://localhost:80/metrics"
+    )
   '';
 })
diff --git a/nixos/tests/hitch/default.nix b/nixos/tests/hitch/default.nix
index cb24c4dcffc2..106120256412 100644
--- a/nixos/tests/hitch/default.nix
+++ b/nixos/tests/hitch/default.nix
@@ -1,4 +1,4 @@
-import ../make-test.nix ({ pkgs, ... }:
+import ../make-test-python.nix ({ pkgs, ... }:
 {
   name = "hitch";
   meta = with pkgs.stdenv.lib.maintainers; {
@@ -23,11 +23,11 @@ import ../make-test.nix ({ pkgs, ... }:
 
   testScript =
     ''
-      startAll;
+      start_all()
 
-      $machine->waitForUnit('multi-user.target');
-      $machine->waitForUnit('hitch.service');
-      $machine->waitForOpenPort(443);
-      $machine->succeed('curl -k https://localhost:443/index.txt | grep "We are all good!"');
+      machine.wait_for_unit("multi-user.target")
+      machine.wait_for_unit("hitch.service")
+      machine.wait_for_open_port(443)
+      assert "We are all good!" in machine.succeed("curl -k https://localhost:443/index.txt")
     '';
 })
diff --git a/nixos/tests/i3wm.nix b/nixos/tests/i3wm.nix
index 8afa845f1e21..126178d11879 100644
--- a/nixos/tests/i3wm.nix
+++ b/nixos/tests/i3wm.nix
@@ -7,7 +7,7 @@ import ./make-test-python.nix ({ pkgs, ...} : {
   machine = { lib, ... }: {
     imports = [ ./common/x11.nix ./common/user-account.nix ];
     services.xserver.displayManager.auto.user = "alice";
-    services.xserver.windowManager.default = lib.mkForce "i3";
+    services.xserver.displayManager.defaultSession = lib.mkForce "none+i3";
     services.xserver.windowManager.i3.enable = true;
   };
 
diff --git a/nixos/tests/initrd-network.nix b/nixos/tests/initrd-network.nix
index ed9b82e2da77..4796ff9b7c8d 100644
--- a/nixos/tests/initrd-network.nix
+++ b/nixos/tests/initrd-network.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ...} : {
+import ./make-test-python.nix ({ pkgs, ...} : {
   name = "initrd-network";
 
   meta.maintainers = [ pkgs.stdenv.lib.maintainers.eelco ];
@@ -15,8 +15,8 @@ import ./make-test.nix ({ pkgs, ...} : {
 
   testScript =
     ''
-      startAll;
-      $machine->waitForUnit("multi-user.target");
-      $machine->succeed("ip link >&2");
+      start_all()
+      machine.wait_for_unit("multi-user.target")
+      machine.succeed("ip link >&2")
     '';
 })
diff --git a/nixos/tests/leaps.nix b/nixos/tests/leaps.nix
index 6163fed56b6f..65b475d734ec 100644
--- a/nixos/tests/leaps.nix
+++ b/nixos/tests/leaps.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs,  ... }:
+import ./make-test-python.nix ({ pkgs,  ... }:
 
 {
   name = "leaps";
@@ -22,9 +22,11 @@ import ./make-test.nix ({ pkgs,  ... }:
 
   testScript =
     ''
-      startAll;
-      $server->waitForOpenPort(6666);
-      $client->waitForUnit("network.target");
-      $client->succeed("${pkgs.curl}/bin/curl http://server:6666/leaps/ | grep -i 'leaps'");
+      start_all()
+      server.wait_for_open_port(6666)
+      client.wait_for_unit("network.target")
+      assert "leaps" in client.succeed(
+          "${pkgs.curl}/bin/curl http://server:6666/leaps/"
+      )
     '';
 })
diff --git a/nixos/tests/lidarr.nix b/nixos/tests/lidarr.nix
index 85fcbd21d8c0..d3f83e5d9145 100644
--- a/nixos/tests/lidarr.nix
+++ b/nixos/tests/lidarr.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ lib, ... }:
+import ./make-test-python.nix ({ lib, ... }:
 
 with lib;
 
@@ -11,8 +11,10 @@ with lib;
     { services.lidarr.enable = true; };
 
   testScript = ''
-    $machine->waitForUnit('lidarr.service');
-    $machine->waitForOpenPort('8686');
-    $machine->succeed("curl --fail http://localhost:8686/");
+    start_all()
+
+    machine.wait_for_unit("lidarr.service")
+    machine.wait_for_open_port("8686")
+    machine.succeed("curl --fail http://localhost:8686/")
   '';
 })
diff --git a/nixos/tests/lightdm.nix b/nixos/tests/lightdm.nix
index ef30f7741e23..46c2ed7ccc59 100644
--- a/nixos/tests/lightdm.nix
+++ b/nixos/tests/lightdm.nix
@@ -8,9 +8,8 @@ import ./make-test-python.nix ({ pkgs, ...} : {
     imports = [ ./common/user-account.nix ];
     services.xserver.enable = true;
     services.xserver.displayManager.lightdm.enable = true;
-    services.xserver.windowManager.default = "icewm";
+    services.xserver.displayManager.defaultSession = "none+icewm";
     services.xserver.windowManager.icewm.enable = true;
-    services.xserver.desktopManager.default = "none";
   };
 
   enableOCR = true;
diff --git a/nixos/tests/mailcatcher.nix b/nixos/tests/mailcatcher.nix
index eb5b606ecc84..2ef38544fe0a 100644
--- a/nixos/tests/mailcatcher.nix
+++ b/nixos/tests/mailcatcher.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ lib, ... }:
+import ./make-test-python.nix ({ lib, ... }:
 
 {
   name = "mailcatcher";
@@ -16,11 +16,15 @@ import ./make-test.nix ({ lib, ... }:
     };
 
   testScript = ''
-    startAll;
+    start_all()
 
-    $machine->waitForUnit('mailcatcher.service');
-    $machine->waitForOpenPort('1025');
-    $machine->succeed('echo "this is the body of the email" | mail -s "subject" root@example.org');
-    $machine->succeed('curl http://localhost:1080/messages/1.source') =~ /this is the body of the email/ or die;
+    machine.wait_for_unit("mailcatcher.service")
+    machine.wait_for_open_port("1025")
+    machine.succeed(
+        'echo "this is the body of the email" | mail -s "subject" root@example.org'
+    )
+    assert "this is the body of the email" in machine.succeed(
+        "curl http://localhost:1080/messages/1.source"
+    )
   '';
 })
diff --git a/nixos/tests/mutable-users.nix b/nixos/tests/mutable-users.nix
index e590703ab2f4..49c7f78b82ed 100644
--- a/nixos/tests/mutable-users.nix
+++ b/nixos/tests/mutable-users.nix
@@ -1,6 +1,6 @@
 # Mutable users tests.
 
-import ./make-test.nix ({ pkgs, ...} : {
+import ./make-test-python.nix ({ pkgs, ...} : {
   name = "mutable-users";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ gleber ];
@@ -19,21 +19,27 @@ import ./make-test.nix ({ pkgs, ...} : {
     immutableSystem = nodes.machine.config.system.build.toplevel;
     mutableSystem = nodes.mutable.config.system.build.toplevel;
   in ''
-    $machine->start();
-    $machine->waitForUnit("default.target");
+    machine.start()
+    machine.wait_for_unit("default.target")
 
     # Machine starts in immutable mode. Add a user and test if reactivating
     # configuration removes the user.
-    $machine->fail("cat /etc/passwd | grep ^foobar:");
-    $machine->succeed("sudo useradd foobar");
-    $machine->succeed("cat /etc/passwd | grep ^foobar:");
-    $machine->succeed("${immutableSystem}/bin/switch-to-configuration test");
-    $machine->fail("cat /etc/passwd | grep ^foobar:");
+    with subtest("Machine in immutable mode"):
+        assert "foobar" not in machine.succeed("cat /etc/passwd")
+        machine.succeed("sudo useradd foobar")
+        assert "foobar" in machine.succeed("cat /etc/passwd")
+        machine.succeed(
+            "${immutableSystem}/bin/switch-to-configuration test"
+        )
+        assert "foobar" not in machine.succeed("cat /etc/passwd")
 
     # In immutable mode passwd is not wrapped, while in mutable mode it is
     # wrapped.
-    $machine->succeed('which passwd | grep /run/current-system/');
-    $machine->succeed("${mutableSystem}/bin/switch-to-configuration test");
-    $machine->succeed('which passwd | grep /run/wrappers/');
+    with subtest("Password is wrapped in mutable mode"):
+        assert "/run/current-system/" in machine.succeed("which passwd")
+        machine.succeed(
+            "${mutableSystem}/bin/switch-to-configuration test"
+        )
+        assert "/run/wrappers/" in machine.succeed("which passwd")
   '';
 })
diff --git a/nixos/tests/mxisd.nix b/nixos/tests/mxisd.nix
index 0039256f5861..b2b60db4d822 100644
--- a/nixos/tests/mxisd.nix
+++ b/nixos/tests/mxisd.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ... } : {
+import ./make-test-python.nix ({ pkgs, ... } : {
 
   name = "mxisd";
   meta = with pkgs.stdenv.lib.maintainers; {
@@ -19,13 +19,12 @@ import ./make-test.nix ({ pkgs, ... } : {
   };
 
   testScript = ''
-    startAll;
-    $server_mxisd->waitForUnit("mxisd.service");
-    $server_mxisd->waitForOpenPort(8090);
-    $server_mxisd->succeed("curl -Ssf \"http://127.0.0.1:8090/_matrix/identity/api/v1\"");
-    $server_ma1sd->waitForUnit("mxisd.service");
-    $server_ma1sd->waitForOpenPort(8090);
-    $server_ma1sd->succeed("curl -Ssf \"http://127.0.0.1:8090/_matrix/identity/api/v1\"")
-
+    start_all()
+    server_mxisd.wait_for_unit("mxisd.service")
+    server_mxisd.wait_for_open_port(8090)
+    server_mxisd.succeed("curl -Ssf 'http://127.0.0.1:8090/_matrix/identity/api/v1'")
+    server_ma1sd.wait_for_unit("mxisd.service")
+    server_ma1sd.wait_for_open_port(8090)
+    server_ma1sd.succeed("curl -Ssf 'http://127.0.0.1:8090/_matrix/identity/api/v1'")
   '';
 })
diff --git a/nixos/tests/nesting.nix b/nixos/tests/nesting.nix
index 1306d6f8e0c5..6388b67a6e40 100644
--- a/nixos/tests/nesting.nix
+++ b/nixos/tests/nesting.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix {
+import ./make-test-python.nix {
   name = "nesting";
   nodes =  {
     clone = { pkgs, ... }: {
@@ -19,24 +19,26 @@ import ./make-test.nix {
     };
   };
   testScript = ''
-    $clone->waitForUnit("default.target");
-    $clone->succeed("cowsay hey");
-    $clone->fail("hello");
+    clone.wait_for_unit("default.target")
+    clone.succeed("cowsay hey")
+    clone.fail("hello")
 
-    # Nested clones do inherit from parent
-    $clone->succeed("/run/current-system/fine-tune/child-1/bin/switch-to-configuration test");
-    $clone->succeed("cowsay hey");
-    $clone->succeed("hello");
+    with subtest("Nested clones do inherit from parent"):
+        clone.succeed(
+            "/run/current-system/fine-tune/child-1/bin/switch-to-configuration test"
+        )
+        clone.succeed("cowsay hey")
+        clone.succeed("hello")
     
+        children.wait_for_unit("default.target")
+        children.succeed("cowsay hey")
+        children.fail("hello")
 
-    $children->waitForUnit("default.target");
-    $children->succeed("cowsay hey");
-    $children->fail("hello");
-
-    # Nested children do not inherit from parent
-    $children->succeed("/run/current-system/fine-tune/child-1/bin/switch-to-configuration test");
-    $children->fail("cowsay hey");
-    $children->succeed("hello");
-
+    with subtest("Nested children do not inherit from parent"):
+        children.succeed(
+            "/run/current-system/fine-tune/child-1/bin/switch-to-configuration test"
+        )
+        children.fail("cowsay hey")
+        children.succeed("hello")
   '';
 }
diff --git a/nixos/tests/networking.nix b/nixos/tests/networking.nix
index e0585d8f1bb4..9448a104073f 100644
--- a/nixos/tests/networking.nix
+++ b/nixos/tests/networking.nix
@@ -4,7 +4,7 @@
 # bool: whether to use networkd in the tests
 , networkd }:
 
-with import ../lib/testing.nix { inherit system pkgs; };
+with import ../lib/testing-python.nix { inherit system pkgs; };
 with pkgs.lib;
 
 let
@@ -75,10 +75,11 @@ let
       machine.networking.useDHCP = false;
       machine.networking.useNetworkd = networkd;
       testScript = ''
-        startAll;
-        $machine->waitForUnit("network.target");
-        $machine->succeed("ip addr show lo | grep -q 'inet 127.0.0.1/8 '");
-        $machine->succeed("ip addr show lo | grep -q 'inet6 ::1/128 '");
+        start_all()
+        machine.wait_for_unit("network.target")
+        loopback_addresses = machine.succeed("ip addr show lo")
+        assert "inet 127.0.0.1/8" in loopback_addresses
+        assert "inet6 ::1/128" in loopback_addresses
       '';
     };
     static = {
@@ -102,35 +103,35 @@ let
       };
       testScript = { ... }:
         ''
-          startAll;
+          start_all()
 
-          $client->waitForUnit("network.target");
-          $router->waitForUnit("network-online.target");
+          client.wait_for_unit("network.target")
+          router.wait_for_unit("network-online.target")
 
-          # Make sure dhcpcd is not started
-          $client->fail("systemctl status dhcpcd.service");
+          with subtest("Make sure dhcpcd is not started"):
+              client.fail("systemctl status dhcpcd.service")
 
-          # Test vlan 1
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.2");
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.3");
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.10");
+          with subtest("Test vlan 1"):
+              client.wait_until_succeeds("ping -c 1 192.168.1.1")
+              client.wait_until_succeeds("ping -c 1 192.168.1.2")
+              client.wait_until_succeeds("ping -c 1 192.168.1.3")
+              client.wait_until_succeeds("ping -c 1 192.168.1.10")
 
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.2");
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.3");
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.10");
+              router.wait_until_succeeds("ping -c 1 192.168.1.1")
+              router.wait_until_succeeds("ping -c 1 192.168.1.2")
+              router.wait_until_succeeds("ping -c 1 192.168.1.3")
+              router.wait_until_succeeds("ping -c 1 192.168.1.10")
 
-          # Test vlan 2
-          $client->waitUntilSucceeds("ping -c 1 192.168.2.1");
-          $client->waitUntilSucceeds("ping -c 1 192.168.2.2");
+          with subtest("Test vlan 2"):
+              client.wait_until_succeeds("ping -c 1 192.168.2.1")
+              client.wait_until_succeeds("ping -c 1 192.168.2.2")
 
-          $router->waitUntilSucceeds("ping -c 1 192.168.2.1");
-          $router->waitUntilSucceeds("ping -c 1 192.168.2.2");
+              router.wait_until_succeeds("ping -c 1 192.168.2.1")
+              router.wait_until_succeeds("ping -c 1 192.168.2.2")
 
-          # Test default gateway
-          $router->waitUntilSucceeds("ping -c 1 192.168.3.1");
-          $client->waitUntilSucceeds("ping -c 1 192.168.3.1");
+          with subtest("Test default gateway"):
+              router.wait_until_succeeds("ping -c 1 192.168.3.1")
+              client.wait_until_succeeds("ping -c 1 192.168.3.1")
         '';
     };
     dhcpSimple = {
@@ -155,38 +156,38 @@ let
       };
       testScript = { ... }:
         ''
-          startAll;
-
-          $client->waitForUnit("network.target");
-          $router->waitForUnit("network-online.target");
-
-          # Wait until we have an ip address on each interface
-          $client->waitUntilSucceeds("ip addr show dev eth1 | grep -q '192.168.1'");
-          $client->waitUntilSucceeds("ip addr show dev eth1 | grep -q 'fd00:1234:5678:1:'");
-          $client->waitUntilSucceeds("ip addr show dev eth2 | grep -q '192.168.2'");
-          $client->waitUntilSucceeds("ip addr show dev eth2 | grep -q 'fd00:1234:5678:2:'");
-
-          # Test vlan 1
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.2");
-          $client->waitUntilSucceeds("ping -c 1 fd00:1234:5678:1::1");
-          $client->waitUntilSucceeds("ping -c 1 fd00:1234:5678:1::2");
-
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.2");
-          $router->waitUntilSucceeds("ping -c 1 fd00:1234:5678:1::1");
-          $router->waitUntilSucceeds("ping -c 1 fd00:1234:5678:1::2");
-
-          # Test vlan 2
-          $client->waitUntilSucceeds("ping -c 1 192.168.2.1");
-          $client->waitUntilSucceeds("ping -c 1 192.168.2.2");
-          $client->waitUntilSucceeds("ping -c 1 fd00:1234:5678:2::1");
-          $client->waitUntilSucceeds("ping -c 1 fd00:1234:5678:2::2");
-
-          $router->waitUntilSucceeds("ping -c 1 192.168.2.1");
-          $router->waitUntilSucceeds("ping -c 1 192.168.2.2");
-          $router->waitUntilSucceeds("ping -c 1 fd00:1234:5678:2::1");
-          $router->waitUntilSucceeds("ping -c 1 fd00:1234:5678:2::2");
+          start_all()
+
+          client.wait_for_unit("network.target")
+          router.wait_for_unit("network-online.target")
+
+          with subtest("Wait until we have an ip address on each interface"):
+              client.wait_until_succeeds("ip addr show dev eth1 | grep -q '192.168.1'")
+              client.wait_until_succeeds("ip addr show dev eth1 | grep -q 'fd00:1234:5678:1:'")
+              client.wait_until_succeeds("ip addr show dev eth2 | grep -q '192.168.2'")
+              client.wait_until_succeeds("ip addr show dev eth2 | grep -q 'fd00:1234:5678:2:'")
+
+          with subtest("Test vlan 1"):
+              client.wait_until_succeeds("ping -c 1 192.168.1.1")
+              client.wait_until_succeeds("ping -c 1 192.168.1.2")
+              client.wait_until_succeeds("ping -c 1 fd00:1234:5678:1::1")
+              client.wait_until_succeeds("ping -c 1 fd00:1234:5678:1::2")
+
+              router.wait_until_succeeds("ping -c 1 192.168.1.1")
+              router.wait_until_succeeds("ping -c 1 192.168.1.2")
+              router.wait_until_succeeds("ping -c 1 fd00:1234:5678:1::1")
+              router.wait_until_succeeds("ping -c 1 fd00:1234:5678:1::2")
+
+          with subtest("Test vlan 2"):
+              client.wait_until_succeeds("ping -c 1 192.168.2.1")
+              client.wait_until_succeeds("ping -c 1 192.168.2.2")
+              client.wait_until_succeeds("ping -c 1 fd00:1234:5678:2::1")
+              client.wait_until_succeeds("ping -c 1 fd00:1234:5678:2::2")
+
+              router.wait_until_succeeds("ping -c 1 192.168.2.1")
+              router.wait_until_succeeds("ping -c 1 192.168.2.2")
+              router.wait_until_succeeds("ping -c 1 fd00:1234:5678:2::1")
+              router.wait_until_succeeds("ping -c 1 fd00:1234:5678:2::2")
         '';
     };
     dhcpOneIf = {
@@ -206,28 +207,28 @@ let
       };
       testScript = { ... }:
         ''
-          startAll;
+          start_all()
 
-          # Wait for networking to come up
-          $client->waitForUnit("network.target");
-          $router->waitForUnit("network.target");
+          with subtest("Wait for networking to come up"):
+              client.wait_for_unit("network.target")
+              router.wait_for_unit("network.target")
 
-          # Wait until we have an ip address on each interface
-          $client->waitUntilSucceeds("ip addr show dev eth1 | grep -q '192.168.1'");
+          with subtest("Wait until we have an ip address on each interface"):
+              client.wait_until_succeeds("ip addr show dev eth1 | grep -q '192.168.1'")
 
-          # Test vlan 1
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.2");
+          with subtest("Test vlan 1"):
+              client.wait_until_succeeds("ping -c 1 192.168.1.1")
+              client.wait_until_succeeds("ping -c 1 192.168.1.2")
 
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.2");
+              router.wait_until_succeeds("ping -c 1 192.168.1.1")
+              router.wait_until_succeeds("ping -c 1 192.168.1.2")
 
-          # Test vlan 2
-          $client->waitUntilSucceeds("ping -c 1 192.168.2.1");
-          $client->fail("ping -c 1 192.168.2.2");
+          with subtest("Test vlan 2"):
+              client.wait_until_succeeds("ping -c 1 192.168.2.1")
+              client.fail("ping -c 1 192.168.2.2")
 
-          $router->waitUntilSucceeds("ping -c 1 192.168.2.1");
-          $router->fail("ping -c 1 192.168.2.2");
+              router.wait_until_succeeds("ping -c 1 192.168.2.1")
+              router.fail("ping -c 1 192.168.2.2")
         '';
     };
     bond = let
@@ -252,18 +253,18 @@ let
       nodes.client2 = node "192.168.1.2";
       testScript = { ... }:
         ''
-          startAll;
+          start_all()
 
-          # Wait for networking to come up
-          $client1->waitForUnit("network.target");
-          $client2->waitForUnit("network.target");
+          with subtest("Wait for networking to come up"):
+              client1.wait_for_unit("network.target")
+              client2.wait_for_unit("network.target")
 
-          # Test bonding
-          $client1->waitUntilSucceeds("ping -c 2 192.168.1.1");
-          $client1->waitUntilSucceeds("ping -c 2 192.168.1.2");
+          with subtest("Test bonding"):
+              client1.wait_until_succeeds("ping -c 2 192.168.1.1")
+              client1.wait_until_succeeds("ping -c 2 192.168.1.2")
 
-          $client2->waitUntilSucceeds("ping -c 2 192.168.1.1");
-          $client2->waitUntilSucceeds("ping -c 2 192.168.1.2");
+              client2.wait_until_succeeds("ping -c 2 192.168.1.1")
+              client2.wait_until_succeeds("ping -c 2 192.168.1.2")
         '';
     };
     bridge = let
@@ -294,25 +295,24 @@ let
       };
       testScript = { ... }:
         ''
-          startAll;
+          start_all()
 
-          # Wait for networking to come up
-          $client1->waitForUnit("network.target");
-          $client2->waitForUnit("network.target");
-          $router->waitForUnit("network.target");
+          with subtest("Wait for networking to come up"):
+              for machine in client1, client2, router:
+                  machine.wait_for_unit("network.target")
 
-          # Test bridging
-          $client1->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $client1->waitUntilSucceeds("ping -c 1 192.168.1.2");
-          $client1->waitUntilSucceeds("ping -c 1 192.168.1.3");
+          with subtest("Test bridging"):
+              client1.wait_until_succeeds("ping -c 1 192.168.1.1")
+              client1.wait_until_succeeds("ping -c 1 192.168.1.2")
+              client1.wait_until_succeeds("ping -c 1 192.168.1.3")
 
-          $client2->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $client2->waitUntilSucceeds("ping -c 1 192.168.1.2");
-          $client2->waitUntilSucceeds("ping -c 1 192.168.1.3");
+              client2.wait_until_succeeds("ping -c 1 192.168.1.1")
+              client2.wait_until_succeeds("ping -c 1 192.168.1.2")
+              client2.wait_until_succeeds("ping -c 1 192.168.1.3")
 
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.2");
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.3");
+              router.wait_until_succeeds("ping -c 1 192.168.1.1")
+              router.wait_until_succeeds("ping -c 1 192.168.1.2")
+              router.wait_until_succeeds("ping -c 1 192.168.1.3")
         '';
     };
     macvlan = {
@@ -340,35 +340,35 @@ let
       };
       testScript = { ... }:
         ''
-          startAll;
-
-          # Wait for networking to come up
-          $client->waitForUnit("network.target");
-          $router->waitForUnit("network.target");
-
-          # Wait until we have an ip address on each interface
-          $client->waitUntilSucceeds("ip addr show dev eth1 | grep -q '192.168.1'");
-          $client->waitUntilSucceeds("ip addr show dev macvlan | grep -q '192.168.1'");
-
-          # Print lots of diagnostic information
-          $router->log('**********************************************');
-          $router->succeed("ip addr >&2");
-          $router->succeed("ip route >&2");
-          $router->execute("iptables-save >&2");
-          $client->log('==============================================');
-          $client->succeed("ip addr >&2");
-          $client->succeed("ip route >&2");
-          $client->execute("iptables-save >&2");
-          $client->log('##############################################');
-
-          # Test macvlan creates routable ips
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.2");
-          $client->waitUntilSucceeds("ping -c 1 192.168.1.3");
-
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.1");
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.2");
-          $router->waitUntilSucceeds("ping -c 1 192.168.1.3");
+          start_all()
+
+          with subtest("Wait for networking to come up"):
+              client.wait_for_unit("network.target")
+              router.wait_for_unit("network.target")
+
+          with subtest("Wait until we have an ip address on each interface"):
+              client.wait_until_succeeds("ip addr show dev eth1 | grep -q '192.168.1'")
+              client.wait_until_succeeds("ip addr show dev macvlan | grep -q '192.168.1'")
+
+          with subtest("Print lots of diagnostic information"):
+              router.log("**********************************************")
+              router.succeed("ip addr >&2")
+              router.succeed("ip route >&2")
+              router.execute("iptables-save >&2")
+              client.log("==============================================")
+              client.succeed("ip addr >&2")
+              client.succeed("ip route >&2")
+              client.execute("iptables-save >&2")
+              client.log("##############################################")
+
+          with subtest("Test macvlan creates routable ips"):
+              client.wait_until_succeeds("ping -c 1 192.168.1.1")
+              client.wait_until_succeeds("ping -c 1 192.168.1.2")
+              client.wait_until_succeeds("ping -c 1 192.168.1.3")
+
+              router.wait_until_succeeds("ping -c 1 192.168.1.1")
+              router.wait_until_succeeds("ping -c 1 192.168.1.2")
+              router.wait_until_succeeds("ping -c 1 192.168.1.3")
         '';
     };
     sit = let
@@ -395,22 +395,22 @@ let
       nodes.client2 = node { address4 = "192.168.1.2"; remote = "192.168.1.1"; address6 = "fc00::2"; };
       testScript = { ... }:
         ''
-          startAll;
+          start_all()
 
-          # Wait for networking to be configured
-          $client1->waitForUnit("network.target");
-          $client2->waitForUnit("network.target");
+          with subtest("Wait for networking to be configured"):
+              client1.wait_for_unit("network.target")
+              client2.wait_for_unit("network.target")
 
-          # Print diagnostic information
-          $client1->succeed("ip addr >&2");
-          $client2->succeed("ip addr >&2");
+              # Print diagnostic information
+              client1.succeed("ip addr >&2")
+              client2.succeed("ip addr >&2")
 
-          # Test ipv6
-          $client1->waitUntilSucceeds("ping -c 1 fc00::1");
-          $client1->waitUntilSucceeds("ping -c 1 fc00::2");
+          with subtest("Test ipv6"):
+              client1.wait_until_succeeds("ping -c 1 fc00::1")
+              client1.wait_until_succeeds("ping -c 1 fc00::2")
 
-          $client2->waitUntilSucceeds("ping -c 1 fc00::1");
-          $client2->waitUntilSucceeds("ping -c 1 fc00::2");
+              client2.wait_until_succeeds("ping -c 1 fc00::1")
+              client2.wait_until_succeeds("ping -c 1 fc00::2")
         '';
     };
     vlan = let
@@ -435,15 +435,15 @@ let
       nodes.client2 = node "192.168.1.2";
       testScript = { ... }:
         ''
-          startAll;
+          start_all()
 
-          # Wait for networking to be configured
-          $client1->waitForUnit("network.target");
-          $client2->waitForUnit("network.target");
+          with subtest("Wait for networking to be configured"):
+              client1.wait_for_unit("network.target")
+              client2.wait_for_unit("network.target")
 
-          # Test vlan is setup
-          $client1->succeed("ip addr show dev vlan >&2");
-          $client2->succeed("ip addr show dev vlan >&2");
+          with subtest("Test vlan is setup"):
+              client1.succeed("ip addr show dev vlan >&2")
+              client2.succeed("ip addr show dev vlan >&2")
         '';
     };
     virtual = {
@@ -464,33 +464,38 @@ let
       };
 
       testScript = ''
-        my $targetList = <<'END';
+        targetList = """
         tap0: tap persist user 0
         tun0: tun persist user 0
-        END
-
-        # Wait for networking to come up
-        $machine->start;
-        $machine->waitForUnit("network-online.target");
-
-        # Test interfaces set up
-        my $list = $machine->succeed("ip tuntap list | sort");
-        "$list" eq "$targetList" or die(
-          "The list of virtual interfaces does not match the expected one:\n",
-          "Result:\n", "$list\n",
-          "Expected:\n", "$targetList\n"
-        );
-
-        # Test interfaces clean up
-        $machine->succeed("systemctl stop network-addresses-tap0");
-        $machine->sleep(10);
-        $machine->succeed("systemctl stop network-addresses-tun0");
-        $machine->sleep(10);
-        my $residue = $machine->succeed("ip tuntap list");
-        $residue eq "" or die(
-          "Some virtual interface has not been properly cleaned:\n",
-          "$residue\n"
-        );
+        """.strip()
+
+        with subtest("Wait for networking to come up"):
+            machine.start()
+            machine.wait_for_unit("network-online.target")
+
+        with subtest("Test interfaces set up"):
+            list = machine.succeed("ip tuntap list | sort").strip()
+            assert (
+                list == targetList
+            ), """
+            The list of virtual interfaces does not match the expected one:
+            Result:
+              {}
+            Expected:
+              {}
+            """.format(
+                list, targetList
+            )
+
+        with subtest("Test interfaces clean up"):
+            machine.succeed("systemctl stop network-addresses-tap0")
+            machine.sleep(10)
+            machine.succeed("systemctl stop network-addresses-tun0")
+            machine.sleep(10)
+            residue = machine.succeed("ip tuntap list")
+            assert (
+                residue is ""
+            ), "Some virtual interface has not been properly cleaned:\n{}".format(residue)
       '';
     };
     privacy = {
@@ -522,7 +527,7 @@ let
           '';
         };
       };
-      nodes.clientWithPrivacy = { pkgs, ... }: with pkgs.lib; {
+      nodes.client_with_privacy = { pkgs, ... }: with pkgs.lib; {
         virtualisation.vlans = [ 1 ];
         networking = {
           useNetworkd = networkd;
@@ -550,25 +555,31 @@ let
       };
       testScript = { ... }:
         ''
-          startAll;
-
-          $client->waitForUnit("network.target");
-          $clientWithPrivacy->waitForUnit("network.target");
-          $router->waitForUnit("network-online.target");
-
-          # Wait until we have an ip address
-          $clientWithPrivacy->waitUntilSucceeds("ip addr show dev eth1 | grep -q 'fd00:1234:5678:1:'");
-          $client->waitUntilSucceeds("ip addr show dev eth1 | grep -q 'fd00:1234:5678:1:'");
-
-          # Test vlan 1
-          $clientWithPrivacy->waitUntilSucceeds("ping -c 1 fd00:1234:5678:1::1");
-          $client->waitUntilSucceeds("ping -c 1 fd00:1234:5678:1::1");
-
-          # Test address used is temporary
-          $clientWithPrivacy->waitUntilSucceeds("! ip route get fd00:1234:5678:1::1 | grep -q ':[a-f0-9]*ff:fe[a-f0-9]*:'");
-
-          # Test address used is EUI-64
-          $client->waitUntilSucceeds("ip route get fd00:1234:5678:1::1 | grep -q ':[a-f0-9]*ff:fe[a-f0-9]*:'");
+          start_all()
+
+          client.wait_for_unit("network.target")
+          client_with_privacy.wait_for_unit("network.target")
+          router.wait_for_unit("network-online.target")
+
+          with subtest("Wait until we have an ip address"):
+              client_with_privacy.wait_until_succeeds(
+                  "ip addr show dev eth1 | grep -q 'fd00:1234:5678:1:'"
+              )
+              client.wait_until_succeeds("ip addr show dev eth1 | grep -q 'fd00:1234:5678:1:'")
+
+          with subtest("Test vlan 1"):
+              client_with_privacy.wait_until_succeeds("ping -c 1 fd00:1234:5678:1::1")
+              client.wait_until_succeeds("ping -c 1 fd00:1234:5678:1::1")
+
+          with subtest("Test address used is temporary"):
+              client_with_privacy.wait_until_succeeds(
+                  "! ip route get fd00:1234:5678:1::1 | grep -q ':[a-f0-9]*ff:fe[a-f0-9]*:'"
+              )
+
+          with subtest("Test address used is EUI-64"):
+              client.wait_until_succeeds(
+                  "ip route get fd00:1234:5678:1::1 | grep -q ':[a-f0-9]*ff:fe[a-f0-9]*:'"
+              )
         '';
     };
     routes = {
@@ -591,47 +602,57 @@ let
       };
 
       testScript = ''
-        my $targetIPv4Table = <<'END';
+        targetIPv4Table = """
         10.0.0.0/16 proto static scope link mtu 1500 
         192.168.1.0/24 proto kernel scope link src 192.168.1.2 
         192.168.2.0/24 via 192.168.1.1 proto static 
-        END
+        """.strip()
 
-        my $targetIPv6Table = <<'END';
+        targetIPv6Table = """
         2001:1470:fffd:2097::/64 proto kernel metric 256 pref medium
         2001:1470:fffd:2098::/64 via fdfd:b3f0::1 proto static metric 1024 pref medium
         fdfd:b3f0::/48 proto static metric 1024 pref medium
-        END
-
-        $machine->start;
-        $machine->waitForUnit("network.target");
-
-        # test routing tables
-        my $ipv4Table = $machine->succeed("ip -4 route list dev eth0 | head -n3");
-        my $ipv6Table = $machine->succeed("ip -6 route list dev eth0 | head -n3");
-        "$ipv4Table" eq "$targetIPv4Table" or die(
-          "The IPv4 routing table does not match the expected one:\n",
-          "Result:\n", "$ipv4Table\n",
-          "Expected:\n", "$targetIPv4Table\n"
-        );
-        "$ipv6Table" eq "$targetIPv6Table" or die(
-          "The IPv6 routing table does not match the expected one:\n",
-          "Result:\n", "$ipv6Table\n",
-          "Expected:\n", "$targetIPv6Table\n"
-        );
-
-        # test clean-up of the tables
-        $machine->succeed("systemctl stop network-addresses-eth0");
-        my $ipv4Residue = $machine->succeed("ip -4 route list dev eth0 | head -n-3");
-        my $ipv6Residue = $machine->succeed("ip -6 route list dev eth0 | head -n-3");
-        $ipv4Residue eq "" or die(
-          "The IPv4 routing table has not been properly cleaned:\n",
-          "$ipv4Residue\n"
-        );
-        $ipv6Residue eq "" or die(
-          "The IPv6 routing table has not been properly cleaned:\n",
-          "$ipv6Residue\n"
-        );
+        """.strip()
+
+        machine.start()
+        machine.wait_for_unit("network.target")
+
+        with subtest("test routing tables"):
+            ipv4Table = machine.succeed("ip -4 route list dev eth0 | head -n3").strip()
+            ipv6Table = machine.succeed("ip -6 route list dev eth0 | head -n3").strip()
+            assert (
+                ipv4Table == targetIPv4Table
+            ), """
+              The IPv4 routing table does not match the expected one:
+                Result:
+                  {}
+                Expected:
+                  {}
+              """.format(
+                ipv4Table, targetIPv4Table
+            )
+            assert (
+                ipv6Table == targetIPv6Table
+            ), """
+              The IPv6 routing table does not match the expected one:
+                Result:
+                  {}
+                Expected:
+                  {}
+              """.format(
+                ipv6Table, targetIPv6Table
+            )
+
+        with subtest("test clean-up of the tables"):
+            machine.succeed("systemctl stop network-addresses-eth0")
+            ipv4Residue = machine.succeed("ip -4 route list dev eth0 | head -n-3").strip()
+            ipv6Residue = machine.succeed("ip -6 route list dev eth0 | head -n-3").strip()
+            assert (
+                ipv4Residue is ""
+            ), "The IPv4 routing table has not been properly cleaned:\n{}".format(ipv4Residue)
+            assert (
+                ipv6Residue is ""
+            ), "The IPv6 routing table has not been properly cleaned:\n{}".format(ipv6Residue)
       '';
     };
   };
diff --git a/nixos/tests/nfs.nix b/nixos/tests/nfs.nix
deleted file mode 100644
index 2f655336e757..000000000000
--- a/nixos/tests/nfs.nix
+++ /dev/null
@@ -1,90 +0,0 @@
-import ./make-test.nix ({ pkgs, version ? 4, ... }:
-
-let
-
-  client =
-    { pkgs, ... }:
-    { fileSystems = pkgs.lib.mkVMOverride
-        [ { mountPoint = "/data";
-            # nfs4 exports the export with fsid=0 as a virtual root directory
-            device = if (version == 4) then "server:/" else "server:/data";
-            fsType = "nfs";
-            options = [ "vers=${toString version}" ];
-          }
-        ];
-      networking.firewall.enable = false; # FIXME: only open statd
-    };
-
-in
-
-{
-  name = "nfs";
-  meta = with pkgs.stdenv.lib.maintainers; {
-    maintainers = [ eelco ];
-  };
-
-  nodes =
-    { client1 = client;
-      client2 = client;
-
-      server =
-        { ... }:
-        { services.nfs.server.enable = true;
-          services.nfs.server.exports =
-            ''
-              /data 192.168.1.0/255.255.255.0(rw,no_root_squash,no_subtree_check,fsid=0)
-            '';
-          services.nfs.server.createMountPoints = true;
-          networking.firewall.enable = false; # FIXME: figure out what ports need to be allowed
-        };
-    };
-
-  testScript =
-    ''
-      $server->waitForUnit("nfs-server");
-      $server->succeed("systemctl start network-online.target");
-      $server->waitForUnit("network-online.target");
-
-      startAll;
-
-      $client1->waitForUnit("data.mount");
-      $client1->succeed("echo bla > /data/foo");
-      $server->succeed("test -e /data/foo");
-
-      $client2->waitForUnit("data.mount");
-      $client2->succeed("echo bla > /data/bar");
-      $server->succeed("test -e /data/bar");
-
-      # Test whether restarting ‘nfs-server’ works correctly.
-      $server->succeed("systemctl restart nfs-server");
-      $client2->succeed("echo bla >> /data/bar"); # will take 90 seconds due to the NFS grace period
-
-      # Test whether we can get a lock.
-      $client2->succeed("time flock -n -s /data/lock true");
-
-      # Test locking: client 1 acquires an exclusive lock, so client 2
-      # should then fail to acquire a shared lock.
-      $client1->succeed("flock -x /data/lock -c 'touch locked; sleep 100000' &");
-      $client1->waitForFile("locked");
-      $client2->fail("flock -n -s /data/lock true");
-
-      # Test whether client 2 obtains the lock if we reset client 1.
-      $client2->succeed("flock -x /data/lock -c 'echo acquired; touch locked; sleep 100000' >&2 &");
-      $client1->crash;
-      $client1->start;
-      $client2->waitForFile("locked");
-
-      # Test whether locks survive a reboot of the server.
-      $client1->waitForUnit("data.mount");
-      $server->shutdown;
-      $server->start;
-      $client1->succeed("touch /data/xyzzy");
-      $client1->fail("time flock -n -s /data/lock true");
-
-      # Test whether unmounting during shutdown happens quickly.
-      my $t1 = time;
-      $client1->shutdown;
-      my $duration = time - $t1;
-      die "shutdown took too long ($duration seconds)" if $duration > 30;
-    '';
-})
diff --git a/nixos/tests/nfs/default.nix b/nixos/tests/nfs/default.nix
new file mode 100644
index 000000000000..6bc803c91b46
--- /dev/null
+++ b/nixos/tests/nfs/default.nix
@@ -0,0 +1,9 @@
+{ version ? 4
+, system ? builtins.currentSystem
+, pkgs ? import ../../.. { inherit system; }
+}: {
+  simple = import ./simple.nix { inherit version system pkgs; };
+} // pkgs.lib.optionalAttrs (version == 4) {
+  # TODO: Test kerberos + nfsv3
+  kerberos = import ./kerberos.nix { inherit version system pkgs; };
+}
diff --git a/nixos/tests/nfs/kerberos.nix b/nixos/tests/nfs/kerberos.nix
new file mode 100644
index 000000000000..1f2d0d453ea0
--- /dev/null
+++ b/nixos/tests/nfs/kerberos.nix
@@ -0,0 +1,133 @@
+import ../make-test-python.nix ({ pkgs, lib, ... }:
+
+with lib;
+
+let
+  krb5 = 
+    { enable = true;
+      domain_realm."nfs.test"   = "NFS.TEST";
+      libdefaults.default_realm = "NFS.TEST";
+      realms."NFS.TEST" =
+        { admin_server = "server.nfs.test";
+          kdc = "server.nfs.test";
+        };
+    };
+
+  hosts =
+    ''
+      192.168.1.1 client.nfs.test
+      192.168.1.2 server.nfs.test
+    '';
+
+  users = {
+    users.alice = {
+        isNormalUser = true;
+        name = "alice";
+        uid = 1000;
+      };
+  };
+
+in
+
+{
+  name = "nfsv4-with-kerberos";
+ 
+  nodes = {
+    client = { lib, ... }:
+      { inherit krb5 users;
+
+        networking.extraHosts = hosts;
+        networking.domain = "nfs.test";
+        networking.hostName = "client";
+
+        fileSystems = lib.mkVMOverride
+          { "/data" = {
+              device  = "server.nfs.test:/";
+              fsType  = "nfs";
+              options = [ "nfsvers=4" "sec=krb5p" "noauto" ];
+            };
+          };
+      };
+
+    server = { lib, ...}:
+      { inherit krb5 users;
+
+        networking.extraHosts = hosts;
+        networking.domain = "nfs.test";
+        networking.hostName = "server";
+
+        networking.firewall.allowedTCPPorts = [
+          111  # rpc
+          2049 # nfs
+          88   # kerberos
+          749  # kerberos admin
+        ];
+
+        services.kerberos_server.enable = true;
+        services.kerberos_server.realms =
+          { "NFS.TEST".acl =
+            [ { access = "all"; principal = "admin/admin"; } ];
+          };
+
+        services.nfs.server.enable = true;
+        services.nfs.server.createMountPoints = true;
+        services.nfs.server.exports =
+          ''
+            /data *(rw,no_root_squash,fsid=0,sec=krb5p)
+          '';
+      };
+  };
+
+  testScript =
+    ''
+      server.succeed("mkdir -p /data/alice")
+      server.succeed("chown alice:users /data/alice")
+
+      # set up kerberos database
+      server.succeed(
+          "kdb5_util create -s -r NFS.TEST -P master_key",
+          "systemctl restart kadmind.service kdc.service",
+      )
+      server.wait_for_unit(f"kadmind.service")
+      server.wait_for_unit(f"kdc.service")
+
+      # create principals
+      server.succeed(
+          "kadmin.local add_principal -randkey nfs/server.nfs.test",
+          "kadmin.local add_principal -randkey nfs/client.nfs.test",
+          "kadmin.local add_principal -pw admin_pw admin/admin",
+          "kadmin.local add_principal -pw alice_pw alice",
+      )
+
+      # add principals to server keytab
+      server.succeed("kadmin.local ktadd nfs/server.nfs.test")
+      server.succeed("systemctl start rpc-gssd.service rpc-svcgssd.service")
+      server.wait_for_unit(f"rpc-gssd.service")
+      server.wait_for_unit(f"rpc-svcgssd.service")
+
+      client.wait_for_unit("network-online.target")
+
+      # add principals to client keytab
+      client.succeed("echo admin_pw | kadmin -p admin/admin ktadd nfs/client.nfs.test")
+      client.succeed("systemctl start rpc-gssd.service")
+      client.wait_for_unit("rpc-gssd.service")
+
+      with subtest("nfs share mounts"):
+          client.succeed("systemctl restart data.mount")
+          client.wait_for_unit("data.mount")
+
+      with subtest("permissions on nfs share are enforced"):
+          client.fail("su alice -c 'ls /data'")
+          client.succeed("su alice -c 'echo alice_pw | kinit'")
+          client.succeed("su alice -c 'ls /data'")
+
+          client.fail("su alice -c 'echo bla >> /data/foo'")
+          client.succeed("su alice -c 'echo bla >> /data/alice/foo'")
+          server.succeed("test -e /data/alice/foo")
+
+      with subtest("uids/gids are mapped correctly on nfs share"):
+          ids = client.succeed("stat -c '%U %G' /data/alice").split()
+          expected = ["alice", "users"]
+          assert ids == expected, f"ids incorrect: got {ids} expected {expected}"
+    '';
+})
diff --git a/nixos/tests/nfs/simple.nix b/nixos/tests/nfs/simple.nix
new file mode 100644
index 000000000000..a1a09ee0f45c
--- /dev/null
+++ b/nixos/tests/nfs/simple.nix
@@ -0,0 +1,94 @@
+import ../make-test-python.nix ({ pkgs, version ? 4, ... }:
+
+let
+
+  client =
+    { pkgs, ... }:
+    { fileSystems = pkgs.lib.mkVMOverride
+        [ { mountPoint = "/data";
+            # nfs4 exports the export with fsid=0 as a virtual root directory
+            device = if (version == 4) then "server:/" else "server:/data";
+            fsType = "nfs";
+            options = [ "vers=${toString version}" ];
+          }
+        ];
+      networking.firewall.enable = false; # FIXME: only open statd
+    };
+
+in
+
+{
+  name = "nfs";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ eelco ];
+  };
+
+  nodes =
+    { client1 = client;
+      client2 = client;
+
+      server =
+        { ... }:
+        { services.nfs.server.enable = true;
+          services.nfs.server.exports =
+            ''
+              /data 192.168.1.0/255.255.255.0(rw,no_root_squash,no_subtree_check,fsid=0)
+            '';
+          services.nfs.server.createMountPoints = true;
+          networking.firewall.enable = false; # FIXME: figure out what ports need to be allowed
+        };
+    };
+
+  testScript =
+    ''
+      import time
+
+      server.wait_for_unit("nfs-server")
+      server.succeed("systemctl start network-online.target")
+      server.wait_for_unit("network-online.target")
+
+      start_all()
+
+      client1.wait_for_unit("data.mount")
+      client1.succeed("echo bla > /data/foo")
+      server.succeed("test -e /data/foo")
+
+      client2.wait_for_unit("data.mount")
+      client2.succeed("echo bla > /data/bar")
+      server.succeed("test -e /data/bar")
+
+      with subtest("restarting 'nfs-server' works correctly"):
+          server.succeed("systemctl restart nfs-server")
+          # will take 90 seconds due to the NFS grace period
+          client2.succeed("echo bla >> /data/bar")
+
+      with subtest("can get a lock"):
+          client2.succeed("time flock -n -s /data/lock true")
+
+      with subtest("client 2 fails to acquire lock held by client 1"):
+          client1.succeed("flock -x /data/lock -c 'touch locked; sleep 100000' &")
+          client1.wait_for_file("locked")
+          client2.fail("flock -n -s /data/lock true")
+
+      with subtest("client 2 obtains lock after resetting client 1"):
+          client2.succeed(
+              "flock -x /data/lock -c 'echo acquired; touch locked; sleep 100000' >&2 &"
+          )
+          client1.crash()
+          client1.start()
+          client2.wait_for_file("locked")
+
+      with subtest("locks survive server reboot"):
+          client1.wait_for_unit("data.mount")
+          server.shutdown()
+          server.start()
+          client1.succeed("touch /data/xyzzy")
+          client1.fail("time flock -n -s /data/lock true")
+
+      with subtest("unmounting during shutdown happens quickly"):
+          t1 = time.monotonic()
+          client1.shutdown()
+          duration = time.monotonic() - t1
+          assert duration < 30, f"shutdown took too long ({duration} seconds)"
+    '';
+})
diff --git a/nixos/tests/nghttpx.nix b/nixos/tests/nghttpx.nix
index 11611bfe1063..d83c1c4cae63 100644
--- a/nixos/tests/nghttpx.nix
+++ b/nixos/tests/nghttpx.nix
@@ -1,7 +1,7 @@
 let
   nginxRoot = "/run/nginx";
 in
-  import ./make-test.nix ({...}: {
+  import ./make-test-python.nix ({...}: {
     name  = "nghttpx";
     nodes = {
       webserver = {
@@ -52,10 +52,10 @@ in
     };
 
     testScript = ''
-      startAll;
+      start_all()
 
-      $webserver->waitForOpenPort("80");
-      $proxy->waitForOpenPort("80");
-      $client->waitUntilSucceeds("curl -s --fail http://proxy/hello-world.txt");
+      webserver.wait_for_open_port("80")
+      proxy.wait_for_open_port("80")
+      client.wait_until_succeeds("curl -s --fail http://proxy/hello-world.txt")
     '';
   })
diff --git a/nixos/tests/novacomd.nix b/nixos/tests/novacomd.nix
index 4eb60c0feb5c..940210dee235 100644
--- a/nixos/tests/novacomd.nix
+++ b/nixos/tests/novacomd.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ...} : {
+import ./make-test-python.nix ({ pkgs, ...} : {
   name = "novacomd";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ dtzWill ];
@@ -9,26 +9,20 @@ import ./make-test.nix ({ pkgs, ...} : {
   };
 
   testScript = ''
-    $machine->waitForUnit("multi-user.target");
+    machine.wait_for_unit("novacomd.service")
 
-    # multi-user.target wants novacomd.service, but let's make sure
-    $machine->waitForUnit("novacomd.service");
+    with subtest("Make sure the daemon is really listening"):
+        machine.wait_for_open_port(6968)
+        machine.succeed("novacom -l")
 
-    # Check status and try connecting with novacom
-    $machine->succeed("systemctl status novacomd.service >&2");
-    # to prevent non-deterministic failure,
-    # make sure the daemon is really listening
-    $machine->waitForOpenPort(6968);
-    $machine->succeed("novacom -l");
+    with subtest("Stop the daemon, double-check novacom fails if daemon isn't working"):
+        machine.stop_job("novacomd")
+        machine.fail("novacom -l")
 
-    # Stop the daemon, double-check novacom fails if daemon isn't working
-    $machine->stopJob("novacomd");
-    $machine->fail("novacom -l");
-
-    # And back again for good measure
-    $machine->startJob("novacomd");
-    # make sure the daemon is really listening
-    $machine->waitForOpenPort(6968);
-    $machine->succeed("novacom -l");
+    with subtest("Make sure the daemon starts back up again"):
+        machine.start_job("novacomd")
+        # make sure the daemon is really listening
+        machine.wait_for_open_port(6968)
+        machine.succeed("novacom -l")
   '';
 })
diff --git a/nixos/tests/nzbget.nix b/nixos/tests/nzbget.nix
index 042ccec98cf6..12d8ed6ea8da 100644
--- a/nixos/tests/nzbget.nix
+++ b/nixos/tests/nzbget.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ...} : {
+import ./make-test-python.nix ({ pkgs, ...} : {
   name = "nzbget";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ aanderse flokli ];
@@ -15,12 +15,16 @@ import ./make-test.nix ({ pkgs, ...} : {
   };
 
   testScript = ''
-    startAll;
+    start_all()
 
-    $server->waitForUnit("nzbget.service");
-    $server->waitForUnit("network.target");
-    $server->waitForOpenPort(6789);
-    $server->succeed("curl -s -u nzbget:tegbzn6789 http://127.0.0.1:6789 | grep -q 'This file is part of nzbget'");
-    $server->succeed("${pkgs.nzbget}/bin/nzbget -n -o ControlIP=127.0.0.1 -o ControlPort=6789 -o ControlPassword=tegbzn6789 -V");
+    server.wait_for_unit("nzbget.service")
+    server.wait_for_unit("network.target")
+    server.wait_for_open_port(6789)
+    assert "This file is part of nzbget" in server.succeed(
+        "curl -s -u nzbget:tegbzn6789 http://127.0.0.1:6789"
+    )
+    server.succeed(
+        "${pkgs.nzbget}/bin/nzbget -n -o Control_iP=127.0.0.1 -o Control_port=6789 -o Control_password=tegbzn6789 -V"
+    )
   '';
 })
diff --git a/nixos/tests/orangefs.nix b/nixos/tests/orangefs.nix
index bdf4fc10c447..46d7a6a72f89 100644
--- a/nixos/tests/orangefs.nix
+++ b/nixos/tests/orangefs.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ ... } :
+import ./make-test-python.nix ({ ... } :
 
 let
   server = { pkgs, ... } : {
@@ -52,37 +52,31 @@ in {
 
   testScript = ''
     # format storage
-    foreach my $server  (($server1,$server2))
-    {
-      $server->start();
-      $server->waitForUnit("multi-user.target");
-      $server->succeed("mkdir -p /data/storage /data/meta");
-      $server->succeed("chown orangefs:orangefs /data/storage /data/meta");
-      $server->succeed("chmod 0770 /data/storage /data/meta");
-      $server->succeed("sudo -g orangefs -u orangefs pvfs2-server -f /etc/orangefs/server.conf");
-    }
+    for server in server1, server2:
+        server.start()
+        server.wait_for_unit("multi-user.target")
+        server.succeed("mkdir -p /data/storage /data/meta")
+        server.succeed("chown orangefs:orangefs /data/storage /data/meta")
+        server.succeed("chmod 0770 /data/storage /data/meta")
+        server.succeed(
+            "sudo -g orangefs -u orangefs pvfs2-server -f /etc/orangefs/server.conf"
+        )
 
     # start services after storage is formated on all machines
-    foreach my $server  (($server1,$server2))
-    {
-      $server->succeed("systemctl start orangefs-server.service");
-    }
+    for server in server1, server2:
+        server.succeed("systemctl start orangefs-server.service")
 
-    # Check if clients can reach and mount the FS
-    foreach my $client  (($client1,$client2))
-    {
-      $client->start();
-      $client->waitForUnit("orangefs-client.service");
-      # Both servers need to be reachable
-      $client->succeed("pvfs2-check-server -h server1 -f orangefs -n tcp -p 3334");
-      $client->succeed("pvfs2-check-server -h server2 -f orangefs -n tcp -p 3334");
-      $client->waitForUnit("orangefs.mount");
-
-    }
-
-    # R/W test between clients
-    $client1->succeed("echo test > /orangefs/file1");
-    $client2->succeed("grep test /orangefs/file1");
+    with subtest("clients can reach and mount the FS"):
+        for client in client1, client2:
+            client.start()
+            client.wait_for_unit("orangefs-client.service")
+            # Both servers need to be reachable
+            client.succeed("pvfs2-check-server -h server1 -f orangefs -n tcp -p 3334")
+            client.succeed("pvfs2-check-server -h server2 -f orangefs -n tcp -p 3334")
+            client.wait_for_unit("orangefs.mount")
 
+    with subtest("R/W test between clients"):
+        client1.succeed("echo test > /orangefs/file1")
+        client2.succeed("grep test /orangefs/file1")
   '';
 })
diff --git a/nixos/tests/osrm-backend.nix b/nixos/tests/osrm-backend.nix
index 6e2d098d4adb..db67a5a589f9 100644
--- a/nixos/tests/osrm-backend.nix
+++ b/nixos/tests/osrm-backend.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, lib, ... }:
+import ./make-test-python.nix ({ pkgs, lib, ... }:
 let
   port = 5000;
 in {
@@ -45,9 +45,13 @@ in {
   testScript = let
     query = "http://localhost:${toString port}/route/v1/driving/7.41720,43.73304;7.42463,43.73886?steps=true";
   in ''
-    $machine->waitForUnit("osrm.service");
-    $machine->waitForOpenPort(${toString port});
-    $machine->succeed("curl --silent '${query}' | jq .waypoints[0].name | grep -F 'Boulevard Rainier III'");
-    $machine->succeed("curl --silent '${query}' | jq .waypoints[1].name | grep -F 'Avenue de la Costa'");
+    machine.wait_for_unit("osrm.service")
+    machine.wait_for_open_port(${toString port})
+    assert "Boulevard Rainier III" in machine.succeed(
+        "curl --silent '${query}' | jq .waypoints[0].name"
+    )
+    assert "Avenue de la Costa" in machine.succeed(
+        "curl --silent '${query}' | jq .waypoints[1].name"
+    )
   '';
 })
diff --git a/nixos/tests/overlayfs.nix b/nixos/tests/overlayfs.nix
index 99bb6b0f5531..33794deb9ed8 100644
--- a/nixos/tests/overlayfs.nix
+++ b/nixos/tests/overlayfs.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ... }: {
+import ./make-test-python.nix ({ pkgs, ... }: {
   name = "overlayfs";
   meta.maintainers = with pkgs.stdenv.lib.maintainers; [ bachp ];
 
@@ -9,49 +9,42 @@ import ./make-test.nix ({ pkgs, ... }: {
   };
 
   testScript = ''
-    $machine->succeed("ls /dev");
+    machine.succeed("ls /dev")
 
-    $machine->succeed("mkdir -p /tmp/mnt");
+    machine.succeed("mkdir -p /tmp/mnt")
 
     # Test ext4 + overlayfs
-    $machine->succeed(
-
-      "mkfs.ext4 -F -L overlay-ext4 /dev/vdb",
-      "mount -t ext4 /dev/vdb /tmp/mnt",
-
-      "mkdir -p /tmp/mnt/upper /tmp/mnt/lower /tmp/mnt/work /tmp/mnt/merged",
-
-      # Setup some existing files
-      "echo 'Replace' > /tmp/mnt/lower/replace.txt",
-      "echo 'Append' > /tmp/mnt/lower/append.txt",
-      "echo 'Overwrite' > /tmp/mnt/lower/overwrite.txt",
-
-      "mount -t overlay overlay -o lowerdir=/tmp/mnt/lower,upperdir=/tmp/mnt/upper,workdir=/tmp/mnt/work /tmp/mnt/merged",
-
-      # Test new
-      "echo 'New' > /tmp/mnt/merged/new.txt",
-      "[[ \"\$(cat /tmp/mnt/merged/new.txt)\" == \"New\" ]]",
-
-      # Test replace
-      "[[ \"\$(cat /tmp/mnt/merged/replace.txt)\" == \"Replace\" ]]",
-      "echo 'Replaced' > /tmp/mnt/merged/replace-tmp.txt",
-      "mv /tmp/mnt/merged/replace-tmp.txt /tmp/mnt/merged/replace.txt",
-      "[[ \"\$(cat /tmp/mnt/merged/replace.txt)\" == \"Replaced\" ]]",
-
-      # Overwrite
-      "[[ \"\$(cat /tmp/mnt/merged/overwrite.txt)\" == \"Overwrite\" ]]",
-      "echo 'Overwritten' > /tmp/mnt/merged/overwrite.txt",
-      "[[ \"\$(cat /tmp/mnt/merged/overwrite.txt)\" == \"Overwritten\" ]]",
-
-      # Test append
-      "[[ \"\$(cat /tmp/mnt/merged/append.txt)\" == \"Append\" ]]",
-      "echo 'ed' >> /tmp/mnt/merged/append.txt",
-      #"cat /tmp/mnt/merged/append.txt && exit 1",
-      "[[ \"\$(cat /tmp/mnt/merged/append.txt)\" == \"Append\ned\" ]]",
-
-      "umount /tmp/mnt/merged",
-      "umount /tmp/mnt",
-      "udevadm settle"
-    );
+    machine.succeed(
+        """
+          mkfs.ext4 -F -L overlay-ext4 /dev/vdb
+          mount -t ext4 /dev/vdb /tmp/mnt
+          mkdir -p /tmp/mnt/upper /tmp/mnt/lower /tmp/mnt/work /tmp/mnt/merged
+          # Setup some existing files
+          echo 'Replace' > /tmp/mnt/lower/replace.txt
+          echo 'Append' > /tmp/mnt/lower/append.txt
+          echo 'Overwrite' > /tmp/mnt/lower/overwrite.txt
+          mount -t overlay overlay -o lowerdir=/tmp/mnt/lower,upperdir=/tmp/mnt/upper,workdir=/tmp/mnt/work /tmp/mnt/merged
+          # Test new
+          echo 'New' > /tmp/mnt/merged/new.txt
+          [[ "\$(cat /tmp/mnt/merged/new.txt)" == "New" ]]
+          # Test replace
+          [[ "\$(cat /tmp/mnt/merged/replace.txt)" == "Replace" ]]
+          echo 'Replaced' > /tmp/mnt/merged/replace-tmp.txt
+          mv /tmp/mnt/merged/replace-tmp.txt /tmp/mnt/merged/replace.txt
+          [[ "\$(cat /tmp/mnt/merged/replace.txt)" == "Replaced" ]]
+          # Overwrite
+          [[ "\$(cat /tmp/mnt/merged/overwrite.txt)" == "Overwrite" ]]
+          echo 'Overwritten' > /tmp/mnt/merged/overwrite.txt
+          [[ "\$(cat /tmp/mnt/merged/overwrite.txt)" == "Overwritten" ]]
+          # Test append
+          [[ "\$(cat /tmp/mnt/merged/append.txt)" == "Append" ]]
+          echo 'ed' >> /tmp/mnt/merged/append.txt
+          #"cat /tmp/mnt/merged/append.txt && exit 1
+          [[ "\$(cat /tmp/mnt/merged/append.txt)" == "Append\ned" ]]
+          umount /tmp/mnt/merged
+          umount /tmp/mnt
+          udevadm settle
+      """
+    )
   '';
 })
diff --git a/nixos/tests/paperless.nix b/nixos/tests/paperless.nix
index 860ad0a6218f..355e7041d3fe 100644
--- a/nixos/tests/paperless.nix
+++ b/nixos/tests/paperless.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ lib, ... } : {
+import ./make-test-python.nix ({ lib, ... } : {
   name = "paperless";
   meta = with lib.maintainers; {
     maintainers = [ earvstedt ];
@@ -13,17 +13,24 @@ import ./make-test.nix ({ lib, ... } : {
   };
 
   testScript = ''
-    $machine->waitForUnit("paperless-consumer.service");
+    machine.wait_for_unit("paperless-consumer.service")
+
     # Create test doc
-    $machine->succeed('convert -size 400x40 xc:white -font "DejaVu-Sans" -pointsize 20 -fill black \
-      -annotate +5+20 "hello world 16-10-2005" /var/lib/paperless/consume/doc.png');
+    machine.succeed(
+        "convert -size 400x40 xc:white -font 'DejaVu-Sans' -pointsize 20 -fill black -annotate +5+20 'hello world 16-10-2005' /var/lib/paperless/consume/doc.png"
+    )
+
+    with subtest("Service gets ready"):
+        machine.wait_for_unit("paperless-server.service")
+        # Wait until server accepts connections
+        machine.wait_until_succeeds("curl -s localhost:28981")
 
-    $machine->waitForUnit("paperless-server.service");
-    # Wait until server accepts connections
-    $machine->waitUntilSucceeds("curl -s localhost:28981");
-    # Wait until document is consumed
-    $machine->waitUntilSucceeds('(($(curl -s localhost:28981/api/documents/ | jq .count) == 1))');
-    $machine->succeed("curl -s localhost:28981/api/documents/ | jq '.results | .[0] | .created'")
-      =~ /2005-10-16/ or die;
+    with subtest("Test document is consumed"):
+        machine.wait_until_succeeds(
+            "(($(curl -s localhost:28981/api/documents/ | jq .count) == 1))"
+        )
+        assert "2005-10-16" in machine.succeed(
+            "curl -s localhost:28981/api/documents/ | jq '.results | .[0] | .created'"
+        )
   '';
 })
diff --git a/nixos/tests/pdns-recursor.nix b/nixos/tests/pdns-recursor.nix
index bf6e6093d69c..de1b60e0b1c7 100644
--- a/nixos/tests/pdns-recursor.nix
+++ b/nixos/tests/pdns-recursor.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ... }: {
+import ./make-test-python.nix ({ pkgs, ... }: {
   name = "powerdns";
 
   nodes.server = { ... }: {
@@ -6,7 +6,7 @@ import ./make-test.nix ({ pkgs, ... }: {
   };
 
   testScript = ''
-    $server->waitForUnit("pdns-recursor");
-    $server->waitForOpenPort("53");
+    server.wait_for_unit("pdns-recursor")
+    server.wait_for_open_port("53")
   '';
 })
diff --git a/nixos/tests/peerflix.nix b/nixos/tests/peerflix.nix
index fae37fedaac7..37628604d49b 100644
--- a/nixos/tests/peerflix.nix
+++ b/nixos/tests/peerflix.nix
@@ -1,6 +1,6 @@
 # This test runs peerflix and checks if peerflix starts
 
-import ./make-test.nix ({ pkgs, ...} : {
+import ./make-test-python.nix ({ pkgs, ...} : {
   name = "peerflix";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ offline ];
@@ -15,9 +15,9 @@ import ./make-test.nix ({ pkgs, ...} : {
     };
 
   testScript = ''
-    startAll;
+    start_all()
 
-    $peerflix->waitForUnit("peerflix.service");
-    $peerflix->waitUntilSucceeds("curl localhost:9000");
+    peerflix.wait_for_unit("peerflix.service")
+    peerflix.wait_until_succeeds("curl localhost:9000")
   '';
 })
diff --git a/nixos/tests/pgmanage.nix b/nixos/tests/pgmanage.nix
index bacaf3f41588..4f5dbed24a97 100644
--- a/nixos/tests/pgmanage.nix
+++ b/nixos/tests/pgmanage.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ... } :
+import ./make-test-python.nix ({ pkgs, ... } :
 let
   role     = "test";
   password = "secret";
@@ -29,11 +29,13 @@ in
   };
 
   testScript = ''
-    startAll;
-    $one->waitForUnit("default.target");
-    $one->requireActiveUnit("pgmanage.service");
+    start_all()
+    one.wait_for_unit("default.target")
+    one.require_unit_state("pgmanage.service", "active")
 
     # Test if we can log in.
-    $one->waitUntilSucceeds("curl 'http://localhost:8080/pgmanage/auth' --data 'action=login&connname=${conn}&username=${role}&password=${password}' --fail");
+    one.wait_until_succeeds(
+        "curl 'http://localhost:8080/pgmanage/auth' --data 'action=login&connname=${conn}&username=${role}&password=${password}' --fail"
+    )
   '';
 })
diff --git a/nixos/tests/php-pcre.nix b/nixos/tests/php-pcre.nix
index ae44aec7944f..d5c22e0582a0 100644
--- a/nixos/tests/php-pcre.nix
+++ b/nixos/tests/php-pcre.nix
@@ -1,7 +1,7 @@
 
 let testString = "can-use-subgroups"; in
 
-import ./make-test.nix ({ ...}: {
+import ./make-test-python.nix ({ ...}: {
   name = "php-httpd-pcre-jit-test";
   machine = { lib, pkgs, ... }: {
     time.timeZone = "UTC";
@@ -31,9 +31,10 @@ import ./make-test.nix ({ ...}: {
   };
   testScript = { ... }:
   ''
-    $machine->waitForUnit('httpd.service');
+    machine.wait_for_unit("httpd.service")
     # Ensure php evaluation by matching on the var_dump syntax
-    $machine->succeed('curl -vvv -s http://127.0.0.1:80/index.php \
-      | grep "string(${toString (builtins.stringLength testString)}) \"${testString}\""');
+    assert 'string(${toString (builtins.stringLength testString)}) "${testString}"' in machine.succeed(
+        "curl -vvv -s http://127.0.0.1:80/index.php"
+    )
   '';
 })
diff --git a/nixos/tests/plasma5.nix b/nixos/tests/plasma5.nix
index 6884f17aabbe..2eccfdf47f59 100644
--- a/nixos/tests/plasma5.nix
+++ b/nixos/tests/plasma5.nix
@@ -12,8 +12,8 @@ import ./make-test-python.nix ({ pkgs, ...} :
     imports = [ ./common/user-account.nix ];
     services.xserver.enable = true;
     services.xserver.displayManager.sddm.enable = true;
+    services.xserver.displayManager.defaultSession = "plasma5";
     services.xserver.desktopManager.plasma5.enable = true;
-    services.xserver.desktopManager.default = "plasma5";
     services.xserver.displayManager.sddm.autoLogin = {
       enable = true;
       user = "alice";
diff --git a/nixos/tests/postgis.nix b/nixos/tests/postgis.nix
index 294eb50b5fe5..84bbb0bc8ec6 100644
--- a/nixos/tests/postgis.nix
+++ b/nixos/tests/postgis.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ...} : {
+import ./make-test-python.nix ({ pkgs, ...} : {
   name = "postgis";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ lsix ];
@@ -20,10 +20,10 @@ import ./make-test.nix ({ pkgs, ...} : {
   };
 
   testScript = ''
-    startAll;
-    $master->waitForUnit("postgresql");
-    $master->sleep(10); # Hopefully this is long enough!!
-    $master->succeed("sudo -u postgres psql -c 'CREATE EXTENSION postgis;'");
-    $master->succeed("sudo -u postgres psql -c 'CREATE EXTENSION postgis_topology;'");
+    start_all()
+    master.wait_for_unit("postgresql")
+    master.sleep(10)  # Hopefully this is long enough!!
+    master.succeed("sudo -u postgres psql -c 'CREATE EXTENSION postgis;'")
+    master.succeed("sudo -u postgres psql -c 'CREATE EXTENSION postgis_topology;'")
   '';
 })
diff --git a/nixos/tests/quagga.nix b/nixos/tests/quagga.nix
index 6aee7ea57f03..04590aa0eb38 100644
--- a/nixos/tests/quagga.nix
+++ b/nixos/tests/quagga.nix
@@ -5,7 +5,7 @@
 #
 # All interfaces are in OSPF Area 0.
 
-import ./make-test.nix ({ pkgs, ... }:
+import ./make-test-python.nix ({ pkgs, ... }:
   let
 
     ifAddr = node: iface: (pkgs.lib.head node.config.networking.interfaces.${iface}.ipv4.addresses).address;
@@ -74,23 +74,23 @@ import ./make-test.nix ({ pkgs, ... }:
       testScript =
         { ... }:
         ''
-          startAll;
+          start_all()
 
           # Wait for the networking to start on all machines
-          $_->waitForUnit("network.target") foreach values %vms;
+          for machine in client, router1, router2, server:
+              machine.wait_for_unit("network.target")
 
-          # Wait for OSPF to form adjacencies
-          for my $gw ($router1, $router2) {
-              $gw->waitForUnit("ospfd");
-              $gw->waitUntilSucceeds("vtysh -c 'show ip ospf neighbor' | grep Full");
-              $gw->waitUntilSucceeds("vtysh -c 'show ip route' | grep '^O>'");
-          }
+          with subtest("Wait for OSPF to form adjacencies"):
+              for gw in router1, router2:
+                  gw.wait_for_unit("ospfd")
+                  gw.wait_until_succeeds("vtysh -c 'show ip ospf neighbor' | grep Full")
+                  gw.wait_until_succeeds("vtysh -c 'show ip route' | grep '^O>'")
 
-          # Test ICMP.
-          $client->succeed("ping -c 3 server >&2");
+          with subtest("Test ICMP"):
+              client.wait_until_succeeds("ping -c 3 server >&2")
 
-          # Test whether HTTP works.
-          $server->waitForUnit("httpd");
-          $client->succeed("curl --fail http://server/ >&2");
+          with subtest("Test whether HTTP works"):
+              server.wait_for_unit("httpd")
+              client.succeed("curl --fail http://server/ >&2")
         '';
     })
diff --git a/nixos/tests/rspamd.nix b/nixos/tests/rspamd.nix
index 0cc94728f80a..bf3f0de62044 100644
--- a/nixos/tests/rspamd.nix
+++ b/nixos/tests/rspamd.nix
@@ -3,20 +3,20 @@
   pkgs ? import ../.. { inherit system config; }
 }:
 
-with import ../lib/testing.nix { inherit system pkgs; };
+with import ../lib/testing-python.nix { inherit system pkgs; };
 with pkgs.lib;
 
 let
   initMachine = ''
-    startAll
-    $machine->waitForUnit("rspamd.service");
-    $machine->succeed("id \"rspamd\" >/dev/null");
+    start_all()
+    machine.wait_for_unit("rspamd.service")
+    machine.succeed("id rspamd >/dev/null")
   '';
   checkSocket = socket: user: group: mode: ''
-    $machine->succeed("ls ${socket} >/dev/null");
-    $machine->succeed("[[ \"\$(stat -c %U ${socket})\" == \"${user}\" ]]");
-    $machine->succeed("[[ \"\$(stat -c %G ${socket})\" == \"${group}\" ]]");
-    $machine->succeed("[[ \"\$(stat -c %a ${socket})\" == \"${mode}\" ]]");
+    machine.succeed("ls ${socket} >/dev/null")
+    machine.succeed('[[ "$(stat -c %U ${socket})" == "${user}" ]]')
+    machine.succeed('[[ "$(stat -c %G ${socket})" == "${group}" ]]')
+    machine.succeed('[[ "$(stat -c %a ${socket})" == "${mode}" ]]')
   '';
   simple = name: enableIPv6: makeTest {
     name = "rspamd-${name}";
@@ -25,22 +25,23 @@ let
       networking.enableIPv6 = enableIPv6;
     };
     testScript = ''
-      startAll
-      $machine->waitForUnit("multi-user.target");
-      $machine->waitForOpenPort(11334);
-      $machine->waitForUnit("rspamd.service");
-      $machine->succeed("id \"rspamd\" >/dev/null");
+      start_all()
+      machine.wait_for_unit("multi-user.target")
+      machine.wait_for_open_port(11334)
+      machine.wait_for_unit("rspamd.service")
+      machine.succeed("id rspamd >/dev/null")
       ${checkSocket "/run/rspamd/rspamd.sock" "rspamd" "rspamd" "660" }
-      sleep 10;
-      $machine->log($machine->succeed("cat /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("grep 'CONFDIR/worker-controller.inc' /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("grep 'CONFDIR/worker-normal.inc' /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("systemctl cat rspamd.service"));
-      $machine->log($machine->succeed("curl http://localhost:11334/auth"));
-      $machine->log($machine->succeed("curl http://127.0.0.1:11334/auth"));
-      ${optionalString enableIPv6 ''
-        $machine->log($machine->succeed("curl http://[::1]:11334/auth"));
-      ''}
+      machine.sleep(10)
+      machine.log(machine.succeed("cat /etc/rspamd/rspamd.conf"))
+      machine.log(
+          machine.succeed("grep 'CONFDIR/worker-controller.inc' /etc/rspamd/rspamd.conf")
+      )
+      machine.log(machine.succeed("grep 'CONFDIR/worker-normal.inc' /etc/rspamd/rspamd.conf"))
+      machine.log(machine.succeed("systemctl cat rspamd.service"))
+      machine.log(machine.succeed("curl http://localhost:11334/auth"))
+      machine.log(machine.succeed("curl http://127.0.0.1:11334/auth"))
+      ${optionalString enableIPv6 ''machine.log(machine.succeed("curl http://[::1]:11334/auth"))''}
+      # would not reformat
     '';
   };
 in
@@ -69,14 +70,18 @@ in
 
     testScript = ''
       ${initMachine}
-      $machine->waitForFile("/run/rspamd.sock");
+      machine.wait_for_file("/run/rspamd.sock")
       ${checkSocket "/run/rspamd.sock" "root" "root" "600" }
       ${checkSocket "/run/rspamd-worker.sock" "root" "root" "666" }
-      $machine->log($machine->succeed("cat /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("grep 'CONFDIR/worker-controller.inc' /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("grep 'CONFDIR/worker-normal.inc' /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("rspamc -h /run/rspamd-worker.sock stat"));
-      $machine->log($machine->succeed("curl --unix-socket /run/rspamd-worker.sock http://localhost/ping"));
+      machine.log(machine.succeed("cat /etc/rspamd/rspamd.conf"))
+      machine.log(
+          machine.succeed("grep 'CONFDIR/worker-controller.inc' /etc/rspamd/rspamd.conf")
+      )
+      machine.log(machine.succeed("grep 'CONFDIR/worker-normal.inc' /etc/rspamd/rspamd.conf"))
+      machine.log(machine.succeed("rspamc -h /run/rspamd-worker.sock stat"))
+      machine.log(
+          machine.succeed("curl --unix-socket /run/rspamd-worker.sock http://localhost/ping")
+      )
     '';
   };
 
@@ -111,18 +116,32 @@ in
 
     testScript = ''
       ${initMachine}
-      $machine->waitForFile("/run/rspamd.sock");
+      machine.wait_for_file("/run/rspamd.sock")
       ${checkSocket "/run/rspamd.sock" "root" "root" "600" }
       ${checkSocket "/run/rspamd-worker.sock" "root" "root" "666" }
-      $machine->log($machine->succeed("cat /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("grep 'CONFDIR/worker-controller.inc' /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("grep 'CONFDIR/worker-normal.inc' /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("grep 'LOCAL_CONFDIR/override.d/worker-controller2.inc' /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("grep 'verysecretpassword' /etc/rspamd/override.d/worker-controller2.inc"));
-      $machine->waitUntilSucceeds("journalctl -u rspamd | grep -i 'starting controller process' >&2");
-      $machine->log($machine->succeed("rspamc -h /run/rspamd-worker.sock stat"));
-      $machine->log($machine->succeed("curl --unix-socket /run/rspamd-worker.sock http://localhost/ping"));
-      $machine->log($machine->succeed("curl http://localhost:11335/ping"));
+      machine.log(machine.succeed("cat /etc/rspamd/rspamd.conf"))
+      machine.log(
+          machine.succeed("grep 'CONFDIR/worker-controller.inc' /etc/rspamd/rspamd.conf")
+      )
+      machine.log(machine.succeed("grep 'CONFDIR/worker-normal.inc' /etc/rspamd/rspamd.conf"))
+      machine.log(
+          machine.succeed(
+              "grep 'LOCAL_CONFDIR/override.d/worker-controller2.inc' /etc/rspamd/rspamd.conf"
+          )
+      )
+      machine.log(
+          machine.succeed(
+              "grep 'verysecretpassword' /etc/rspamd/override.d/worker-controller2.inc"
+          )
+      )
+      machine.wait_until_succeeds(
+          "journalctl -u rspamd | grep -i 'starting controller process' >&2"
+      )
+      machine.log(machine.succeed("rspamc -h /run/rspamd-worker.sock stat"))
+      machine.log(
+          machine.succeed("curl --unix-socket /run/rspamd-worker.sock http://localhost/ping")
+      )
+      machine.log(machine.succeed("curl http://localhost:11335/ping"))
     '';
   };
   customLuaRules = makeTest {
@@ -199,22 +218,34 @@ in
     };
     testScript = ''
       ${initMachine}
-      $machine->waitForOpenPort(11334);
-      $machine->log($machine->succeed("cat /etc/rspamd/rspamd.conf"));
-      $machine->log($machine->succeed("cat /etc/rspamd/rspamd.local.lua"));
-      $machine->log($machine->succeed("cat /etc/rspamd/local.d/groups.conf"));
+      machine.wait_for_open_port(11334)
+      machine.log(machine.succeed("cat /etc/rspamd/rspamd.conf"))
+      machine.log(machine.succeed("cat /etc/rspamd/rspamd.local.lua"))
+      machine.log(machine.succeed("cat /etc/rspamd/local.d/groups.conf"))
       # Verify that redis.conf was not written
-      $machine->fail("cat /etc/rspamd/local.d/redis.conf >&2");
+      machine.fail("cat /etc/rspamd/local.d/redis.conf >&2")
       # Verify that antivirus.conf was not written
-      $machine->fail("cat /etc/rspamd/local.d/antivirus.conf >&2");
+      machine.fail("cat /etc/rspamd/local.d/antivirus.conf >&2")
       ${checkSocket "/run/rspamd/rspamd.sock" "rspamd" "rspamd" "660" }
-      $machine->log($machine->succeed("curl --unix-socket /run/rspamd/rspamd.sock http://localhost/ping"));
-      $machine->log($machine->succeed("rspamc -h 127.0.0.1:11334 stat"));
-      $machine->log($machine->succeed("cat /etc/tests/no-muh.eml | rspamc -h 127.0.0.1:11334"));
-      $machine->log($machine->succeed("cat /etc/tests/muh.eml | rspamc -h 127.0.0.1:11334 symbols"));
-      $machine->waitUntilSucceeds("journalctl -u rspamd | grep -i muh >&2");
-      $machine->log($machine->fail("cat /etc/tests/no-muh.eml | rspamc -h 127.0.0.1:11334 symbols | grep NO_MUH"));
-      $machine->log($machine->succeed("cat /etc/tests/muh.eml | rspamc -h 127.0.0.1:11334 symbols | grep NO_MUH"));
+      machine.log(
+          machine.succeed("curl --unix-socket /run/rspamd/rspamd.sock http://localhost/ping")
+      )
+      machine.log(machine.succeed("rspamc -h 127.0.0.1:11334 stat"))
+      machine.log(machine.succeed("cat /etc/tests/no-muh.eml | rspamc -h 127.0.0.1:11334"))
+      machine.log(
+          machine.succeed("cat /etc/tests/muh.eml | rspamc -h 127.0.0.1:11334 symbols")
+      )
+      machine.wait_until_succeeds("journalctl -u rspamd | grep -i muh >&2")
+      machine.log(
+          machine.fail(
+              "cat /etc/tests/no-muh.eml | rspamc -h 127.0.0.1:11334 symbols | grep NO_MUH"
+          )
+      )
+      machine.log(
+          machine.succeed(
+              "cat /etc/tests/muh.eml | rspamc -h 127.0.0.1:11334 symbols | grep NO_MUH"
+          )
+      )
     '';
   };
   postfixIntegration = makeTest {
@@ -250,16 +281,24 @@ in
     };
     testScript = ''
       ${initMachine}
-      $machine->waitForOpenPort(11334);
-      $machine->waitForOpenPort(25);
+      machine.wait_for_open_port(11334)
+      machine.wait_for_open_port(25)
       ${checkSocket "/run/rspamd/rspamd-milter.sock" "rspamd" "postfix" "660" }
-      $machine->log($machine->succeed("rspamc -h 127.0.0.1:11334 stat"));
-      $machine->log($machine->succeed("msmtp --host=localhost -t --read-envelope-from < /etc/tests/example.eml"));
-      $machine->log($machine->fail("msmtp --host=localhost -t --read-envelope-from < /etc/tests/gtube.eml"));
+      machine.log(machine.succeed("rspamc -h 127.0.0.1:11334 stat"))
+      machine.log(
+          machine.succeed(
+              "msmtp --host=localhost -t --read-envelope-from < /etc/tests/example.eml"
+          )
+      )
+      machine.log(
+          machine.fail(
+              "msmtp --host=localhost -t --read-envelope-from < /etc/tests/gtube.eml"
+          )
+      )
 
-      $machine->waitUntilFails('[ "$(postqueue -p)" != "Mail queue is empty" ]');
-      $machine->fail("journalctl -u postfix | grep -i error >&2");
-      $machine->fail("journalctl -u postfix | grep -i warning >&2");
+      machine.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+      machine.fail("journalctl -u postfix | grep -i error >&2")
+      machine.fail("journalctl -u postfix | grep -i warning >&2")
     '';
   };
 }
diff --git a/nixos/tests/sddm.nix b/nixos/tests/sddm.nix
index 4bdcd701dcf1..a145705250f7 100644
--- a/nixos/tests/sddm.nix
+++ b/nixos/tests/sddm.nix
@@ -16,9 +16,8 @@ let
         imports = [ ./common/user-account.nix ];
         services.xserver.enable = true;
         services.xserver.displayManager.sddm.enable = true;
-        services.xserver.windowManager.default = "icewm";
+        services.xserver.displayManager.defaultSession = "none+icewm";
         services.xserver.windowManager.icewm.enable = true;
-        services.xserver.desktopManager.default = "none";
       };
 
       enableOCR = true;
@@ -52,9 +51,8 @@ let
             user = "alice";
           };
         };
-        services.xserver.windowManager.default = "icewm";
+        services.xserver.displayManager.defaultSession = "none+icewm";
         services.xserver.windowManager.icewm.enable = true;
-        services.xserver.desktopManager.default = "none";
       };
 
       testScript = { nodes, ... }: let
diff --git a/nixos/tests/sonarr.nix b/nixos/tests/sonarr.nix
index 3e84445099ab..764a4d05b381 100644
--- a/nixos/tests/sonarr.nix
+++ b/nixos/tests/sonarr.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ lib, ... }:
+import ./make-test-python.nix ({ lib, ... }:
 
 with lib;
 
@@ -11,8 +11,8 @@ with lib;
     { services.sonarr.enable = true; };
 
   testScript = ''
-    $machine->waitForUnit('sonarr.service');
-    $machine->waitForOpenPort('8989');
-    $machine->succeed("curl --fail http://localhost:8989/");
+    machine.wait_for_unit("sonarr.service")
+    machine.wait_for_open_port("8989")
+    machine.succeed("curl --fail http://localhost:8989/")
   '';
 })
diff --git a/nixos/tests/switch-test.nix b/nixos/tests/switch-test.nix
index 0dba3697980f..7076bd77b770 100644
--- a/nixos/tests/switch-test.nix
+++ b/nixos/tests/switch-test.nix
@@ -1,6 +1,6 @@
 # Test configuration switching.
 
-import ./make-test.nix ({ pkgs, ...} : {
+import ./make-test-python.nix ({ pkgs, ...} : {
   name = "switch-test";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ gleber ];
@@ -28,7 +28,11 @@ import ./make-test.nix ({ pkgs, ...} : {
       exec env -i "$@" | tee /dev/stderr
     '';
   in ''
-    $machine->succeed("${stderrRunner} ${originalSystem}/bin/switch-to-configuration test");
-    $machine->succeed("${stderrRunner} ${otherSystem}/bin/switch-to-configuration test");
+    machine.succeed(
+        "${stderrRunner} ${originalSystem}/bin/switch-to-configuration test"
+    )
+    machine.succeed(
+        "${stderrRunner} ${otherSystem}/bin/switch-to-configuration test"
+    )
   '';
 })
diff --git a/nixos/tests/systemd-timesyncd.nix b/nixos/tests/systemd-timesyncd.nix
index d12b8eb2bf7e..ad5b9a47383b 100644
--- a/nixos/tests/systemd-timesyncd.nix
+++ b/nixos/tests/systemd-timesyncd.nix
@@ -1,7 +1,7 @@
 # Regression test for systemd-timesync having moved the state directory without
 # upstream providing a migration path. https://github.com/systemd/systemd/issues/12131
 
-import ./make-test.nix (let
+import ./make-test-python.nix (let
   common = { lib, ... }: {
     # override the `false` value from the qemu-vm base profile
     services.timesyncd.enable = lib.mkForce true;
@@ -25,28 +25,28 @@ in {
   };
 
   testScript = ''
-    startAll;
-    $current->succeed('systemctl status systemd-timesyncd.service');
+    start_all()
+    current.succeed("systemctl status systemd-timesyncd.service")
     # on a new install with a recent systemd there should not be any
     # leftovers from the dynamic user mess
-    $current->succeed('test -e /var/lib/systemd/timesync');
-    $current->succeed('test ! -L /var/lib/systemd/timesync');
+    current.succeed("test -e /var/lib/systemd/timesync")
+    current.succeed("test ! -L /var/lib/systemd/timesync")
 
     # timesyncd should be running on the upgrading system since we fixed the
     # file bits in the activation script
-    $pre1909->succeed('systemctl status systemd-timesyncd.service');
+    pre1909.succeed("systemctl status systemd-timesyncd.service")
 
     # the path should be gone after the migration
-    $pre1909->succeed('test ! -e /var/lib/private/systemd/timesync');
+    pre1909.succeed("test ! -e /var/lib/private/systemd/timesync")
 
     # and the new path should no longer be a symlink
-    $pre1909->succeed('test -e /var/lib/systemd/timesync');
-    $pre1909->succeed('test ! -L /var/lib/systemd/timesync');
+    pre1909.succeed("test -e /var/lib/systemd/timesync")
+    pre1909.succeed("test ! -L /var/lib/systemd/timesync")
 
     # after a restart things should still work and not fail in the activation
     # scripts and cause the boot to fail..
-    $pre1909->shutdown;
-    $pre1909->start;
-    $pre1909->succeed('systemctl status systemd-timesyncd.service');
+    pre1909.shutdown()
+    pre1909.start()
+    pre1909.succeed("systemctl status systemd-timesyncd.service")
   '';
 })
diff --git a/nixos/tests/wireguard/namespaces.nix b/nixos/tests/wireguard/namespaces.nix
index 94f993d9475d..c8a4e3bb52a1 100644
--- a/nixos/tests/wireguard/namespaces.nix
+++ b/nixos/tests/wireguard/namespaces.nix
@@ -13,7 +13,7 @@ let
 
 in
 
-import ../make-test.nix ({ pkgs, ...} : {
+import ../make-test-python.nix ({ pkgs, ...} : {
   name = "wireguard-with-namespaces";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ asymmetric ];
@@ -65,16 +65,14 @@ import ../make-test.nix ({ pkgs, ...} : {
   };
 
   testScript = ''
-    startAll();
+    start_all()
 
-    $peer0->waitForUnit("wireguard-wg0.service");
-    $peer1->waitForUnit("wireguard-wg0.service");
-    $peer2->waitForUnit("wireguard-wg0.service");
-    $peer3->waitForUnit("wireguard-wg0.service");
+    for machine in peer0, peer1, peer2, peer3:
+        machine.wait_for_unit("wireguard-wg0.service")
 
-    $peer0->succeed("ip -n ${socketNamespace} link show wg0");
-    $peer1->succeed("ip -n ${interfaceNamespace} link show wg0");
-    $peer2->succeed("ip -n ${interfaceNamespace} link show wg0");
-    $peer3->succeed("ip link show wg0");
+    peer0.succeed("ip -n ${socketNamespace} link show wg0")
+    peer1.succeed("ip -n ${interfaceNamespace} link show wg0")
+    peer2.succeed("ip -n ${interfaceNamespace} link show wg0")
+    peer3.succeed("ip link show wg0")
   '';
 })
diff --git a/nixos/tests/xmonad.nix b/nixos/tests/xmonad.nix
index c2e5ba60d7bc..ef711f8dcf6a 100644
--- a/nixos/tests/xmonad.nix
+++ b/nixos/tests/xmonad.nix
@@ -4,10 +4,10 @@ import ./make-test-python.nix ({ pkgs, ...} : {
     maintainers = [ nequissimus ];
   };
 
-  machine = { lib, pkgs, ... }: {
+  machine = { pkgs, ... }: {
     imports = [ ./common/x11.nix ./common/user-account.nix ];
     services.xserver.displayManager.auto.user = "alice";
-    services.xserver.windowManager.default = lib.mkForce "xmonad";
+    services.xserver.displayManager.defaultSession = "none+xmonad";
     services.xserver.windowManager.xmonad = {
       enable = true;
       enableContribAndExtras = true;
@@ -27,13 +27,13 @@ import ./make-test-python.nix ({ pkgs, ...} : {
     machine.wait_for_x()
     machine.wait_for_file("${user.home}/.Xauthority")
     machine.succeed("xauth merge ${user.home}/.Xauthority")
-    machine.send_chars("alt-ctrl-x")
+    machine.send_key("alt-ctrl-x")
     machine.wait_for_window("${user.name}.*machine")
     machine.sleep(1)
     machine.screenshot("terminal")
     machine.wait_until_succeeds("xmonad --restart")
     machine.sleep(3)
-    machine.send_chars("alt-shift-ret")
+    machine.send_key("alt-shift-ret")
     machine.wait_for_window("${user.name}.*machine")
     machine.sleep(1)
     machine.screenshot("terminal")
diff --git a/nixos/tests/zsh-history.nix b/nixos/tests/zsh-history.nix
new file mode 100644
index 000000000000..4380ec9adfd2
--- /dev/null
+++ b/nixos/tests/zsh-history.nix
@@ -0,0 +1,35 @@
+import ./make-test-python.nix ({ pkgs, ...} : {
+  name = "zsh-history";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ kampka ];
+  };
+
+  nodes.default = { ... }: {
+    programs = {
+      zsh.enable = true;
+    };
+    environment.systemPackages = [ pkgs.zsh-history ];
+    programs.zsh.interactiveShellInit = ''
+      source ${pkgs.zsh-history.out}/share/zsh/init.zsh
+    '';
+    users.users.root.shell = "${pkgs.zsh}/bin/zsh";
+  };
+
+  testScript = ''
+    start_all()
+    default.wait_for_unit("multi-user.target")
+    default.wait_until_succeeds("pgrep -f 'agetty.*tty1'")
+
+    # Login
+    default.wait_until_tty_matches(1, "login: ")
+    default.send_chars("root\n")
+    default.wait_until_tty_matches(1, "root@default>")
+
+    # Generate some history
+    default.send_chars("echo foobar\n")
+    default.wait_until_tty_matches(1, "foobar")
+
+    # Ensure that command was recorded in history
+    default.succeed("/run/current-system/sw/bin/history list | grep -q foobar")
+  '';
+})