1 files changed, 56 insertions, 0 deletions
diff --git a/nixpkgs/nixos/tests/btrbk-section-order.nix b/nixpkgs/nixos/tests/btrbk-section-order.nix
new file mode 100644
index 000000000000..6082de947f66
--- /dev/null
+++ b/nixpkgs/nixos/tests/btrbk-section-order.nix
@@ -0,0 +1,56 @@
+# This tests validates the order of generated sections that may contain
+# other sections.
+# When a `volume` section has both `subvolume` and `target` children,
+# `target` must go before `subvolume`. Otherwise, `target` will become
+# a child of the last `subvolume` instead of `volume`, due to the
+# order-sensitive config format.
+#
+# Issue: https://github.com/NixOS/nixpkgs/issues/195660
+import ./make-test-python.nix ({ lib, pkgs, ... }: {
+  name = "btrbk-section-order";
+  meta.maintainers = with lib.maintainers; [ oxalica ];
+
+  nodes.machine = { ... }: {
+    services.btrbk.instances.local = {
+      onCalendar = null;
+      settings = {
+        timestamp_format = "long";
+        target."ssh://global-target/".ssh_user = "root";
+        volume."/btrfs" = {
+          snapshot_dir = "/volume-snapshots";
+          target."ssh://volume-target/".ssh_user = "root";
+          subvolume."@subvolume" = {
+            snapshot_dir = "/subvolume-snapshots";
+            target."ssh://subvolume-target/".ssh_user = "root";
+          };
+        };
+      };
+    };
+  };
+
+  testScript = ''
+    import difflib
+    machine.wait_for_unit("basic.target")
+    got = machine.succeed("cat /etc/btrbk/local.conf").strip()
+    expect = """
+    backend btrfs-progs-sudo
+    stream_compress no
+    timestamp_format long
+    target ssh://global-target/
+     ssh_user root
+    volume /btrfs
+     snapshot_dir /volume-snapshots
+     target ssh://volume-target/
+      ssh_user root
+     subvolume @subvolume
+      snapshot_dir /subvolume-snapshots
+      target ssh://subvolume-target/
+       ssh_user root
+    """.strip()
+    print(got)
+    if got != expect:
+      diff = difflib.unified_diff(expect.splitlines(keepends=True), got.splitlines(keepends=True), fromfile="expected", tofile="got")
+      print("".join(diff))
+    assert got == expect
+  '';
+})