machine tests take two

flake/tests/default.nix

@@ -0,0 +1,42 @@
+{
+  inputs,
+  self,
+  config,
+  lib,
+  ...
+}: {
+  perSystem = {pkgs, ...}: let
+    inherit (lib.filesystem) packagesFromDirectoryRecursive;
+    inherit (lib.customisation) callPackageWith;
+    inherit (lib.attrsets) recursiveUpdate;
+
+    # Attribute set containing paths to specific profiles. This is meant to be
+    # an easy path to where profiles are defined as the tests directory gets
+    # more complicated, and allow easier renames.
+    profiles = {
+      # Minimal profile is small and lightweight. Plugins that require dependencies
+      # or tests that are resource intensive should not use the minimal profile.
+      minimal = ./profiles/minimal.nix;
+    };
+
+    modules = {
+      nixos = config.flake.nixosModules;
+      home-manager = config.flake.homeManagerModules;
+    };
+
+    # Call tests with preset special arguments.
+    defaultInherits = {inherit inputs profiles modules;};
+    callPackage = callPackageWith (recursiveUpdate pkgs defaultInherits);
+    checkPackages = packagesFromDirectoryRecursive {
+      inherit callPackage;
+      directory = ./checks;
+    };
+  in {
+    # Machine tests that will be ran either manually with 'nix build .#checks.<system>.<check>'
+    # or automatically on 'nix flake check' unless '--no-build-checks' has been passed to it.
+    # We merge 'config.legacyPackages' here to make sure we also build and check plugin packages
+    # that are declared in legacyPackages are built as well, which is usually reserved to Neovim
+    # plugins tracked with npins.
+    checks = checkPackages;
+  };
+}