flake: groundwork for VM tests

Removes basic check packages in favor of proper VM testing infrastructure.

.gitignore

@@ -0,0 +1,3 @@
+# Nix build/test artifacts
+.nixos-test-history
+result*

checks/default.nix

@@ -1,38 +0,0 @@
-{inputs, ...}: let
-  inherit (inputs) self nixpkgs;
-  systems = ["x86_64-linux" "aarch64-linux"];
-  forEachSystem = inputs.nixpkgs.lib.genAttrs systems;
-in
-  forEachSystem (system: let
-    pkgs = nixpkgs.legacyPackages.${system};
-    baseSystem = nixpkgs.lib.nixosSystem {
-      modules = [
-        ({modulesPath, ...}: {
-          imports = [
-            # Minimal profile
-            "${modulesPath}/profiles/minimal.nix"
-
-            # Hjem NixOS module
-            self.nixosModules.hjem
-          ];
-
-          boot.loader.grub.enable = false;
-          fileSystems."/".device = "nodev";
-          nixpkgs.hostPlatform = system;
-          system.stateVersion = "24.11";
-
-          # Hjem setup
-          users.groups.alice = {};
-          users.users.alice.isNormalUser = true;
-          homes = {
-            alice = {
-              files.".config/foo".text = "Hello world!";
-              packages = [pkgs.hello];
-            };
-          };
-        })
-      ];
-    };
-  in {
-    default = baseSystem.config.system.build.toplevel;
-  })

flake.nix

@@ -5,14 +5,23 @@
     self,
     nixpkgs,
     ...
-  } @ inputs: {
+  }: let
+    forAllSystems = nixpkgs.lib.genAttrs ["x86_64-linux" "aarch64-linux"];
+  in {
     nixosModules = {
       hjem = ./modules/nixos.nix;
       default = self.nixosModules.hjem;
     };
 
-    checks = import ./checks {inherit inputs;};
+    checks = forAllSystems (system: let
+      checkArgs = {
+        inherit self;
+        pkgs = nixpkgs.legacyPackages.${system};
+      };
+    in {
+      hjem-basic = import ./tests/basic.nix checkArgs;
+    });
 
-    formatter = nixpkgs.lib.genAttrs ["x86_64-linux" "aarch64-linux"] (system: nixpkgs.legacyPackages.${system}.alejandra);
+    formatter = forAllSystems (system: nixpkgs.legacyPackages.${system}.alejandra);
   };
 }

tests/basic.nix

@@ -0,0 +1,55 @@
+let
+  userHome = "/home/alice";
+in
+  (import ./lib.nix) {
+    name = "hjem-basic";
+    nodes = {
+      node1 = {
+        self,
+        pkgs,
+        ...
+      }: {
+        imports = [self.nixosModules.hjem];
+
+        users.groups.alice = {};
+        users.users.alice = {
+          isNormalUser = true;
+          home = userHome;
+          password = "";
+        };
+
+        homes = {
+          alice = {
+            enable = true;
+            packages = [pkgs.hello];
+            files.".config/foo" = {
+              text = "Hello world!";
+            };
+          };
+        };
+
+        # Also test systemd-tmpfiles internally
+        systemd.user.tmpfiles = {
+          rules = [
+            "d %h/user_tmpfiles_created"
+          ];
+
+          users.alice.rules = [
+            "d %h/only_alice"
+          ];
+        };
+      };
+    };
+
+    testScript = ''
+      machine.succeed("loginctl enable-linger alice")
+      machine.wait_until_succeeds("systemctl --user --machine=alice@ is-active systemd-tmpfiles-setup.service")
+
+      # Test file created by Hjem
+      machine.succeed("[ -L ~alice/.config/foo ]")
+
+      # Test regular files, created by systemd-tmpfiles
+      machine.succeed("[ -d ~alice/user_tmpfiles_created ]")
+      machine.succeed("[ -d ~alice/only_alice ]")
+    '';
+  }

tests/lib.nix

@@ -0,0 +1,17 @@
+# The first argument to this function is the test module itself
+test: {
+  pkgs,
+  self,
+}: let
+  inherit (pkgs) lib;
+  nixos-lib = import (pkgs.path + "/nixos/lib") {};
+in
+  (nixos-lib.runTest {
+    hostPkgs = pkgs;
+    defaults.documentation.enable = lib.mkDefault false;
+
+    node.specialArgs = {inherit self;};
+    imports = [test];
+  })
+  .config
+  .result