nixos/tests: test SDDM with KDE 5 enabled

nixos/release.nix

···
   tests.quake3 = callTest tests/quake3.nix {};
   tests.runInMachine = callTest tests/run-in-machine.nix {};
   tests.sddm = callTest tests/sddm.nix {};
+  tests.sddm-kde5 = callTest tests/sddm-kde5.nix {};
   tests.simple = callTest tests/simple.nix {};
   tests.tomcat = callTest tests/tomcat.nix {};
   tests.udisks2 = callTest tests/udisks2.nix {};

nixos/tests/sddm-kde5.nix

···
+import ./make-test.nix ({ pkgs, ...} : {
+  name = "sddm";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ ttuegel ];
+  };
+
+  machine = { lib, ... }: {
+    imports = [ ./common/user-account.nix ];
+    services.xserver.enable = true;
+    services.xserver.displayManager.sddm = {
+      enable = true;
+      autoLogin = {
+        enable = true;
+        user = "alice";
+      };
+    };
+    services.xserver.windowManager.default = "icewm";
+    services.xserver.windowManager.icewm.enable = true;
+    services.xserver.desktopManager.default = "none";
+    services.xserver.desktopManager.kde5.enable = true;
+  };
+
+  enableOCR = true;
+
+  testScript = { nodes, ... }: ''
+    startAll;
+    $machine->waitForWindow("^IceWM ");
+  '';
+})