1 files changed, 41 insertions, 0 deletions
diff --git a/nixpkgs/lib/tests/modules/docs.nix b/nixpkgs/lib/tests/modules/docs.nix
new file mode 100644
index 000000000000..225aa7eac1de
--- /dev/null
+++ b/nixpkgs/lib/tests/modules/docs.nix
@@ -0,0 +1,41 @@
+/*
+  A basic documentation generating module.
+  Declares and defines a `docs` option, suitable for making assertions about
+  the extraction "phase" of documentation generation.
+ */
+{ lib, options, ... }:
+
+let
+  inherit (lib)
+    head
+    length
+    mkOption
+    types
+  ;
+
+  traceListSeq = l: v: lib.foldl' (a: b: lib.traceSeq b a) v l;
+
+in
+
+{
+  options.docs = mkOption {
+    type = types.lazyAttrsOf types.raw;
+    description = ''
+      All options to be rendered, without any visibility filtering applied.
+    '';
+  };
+  config.docs =
+    lib.zipAttrsWith
+      (name: values:
+        if length values > 1 then
+          traceListSeq values
+          abort "Multiple options with the same name: ${name}"
+        else
+          assert length values == 1;
+          head values
+      )
+      (map
+        (opt: { ${opt.name} = opt; })
+        (lib.optionAttrSetToDocList options)
+      );
+}