nixosTests.{qtile,qtile-extras}: Use startup hook to determine when wm is ready

nixos/tests/all-tests.nix

@@ -1250,7 +1250,7 @@ in
   qgis = handleTest ./qgis.nix { package = pkgs.qgis; };
   qgis-ltr = handleTest ./qgis.nix { package = pkgs.qgis-ltr; };
   qownnotes = runTest ./qownnotes.nix;
-  qtile = runTestOn [ "x86_64-linux" "aarch64-linux" ] ./qtile.nix;
+  qtile = runTestOn [ "x86_64-linux" "aarch64-linux" ] ./qtile/default.nix;
   qtile-extras = runTestOn [ "x86_64-linux" "aarch64-linux" ] ./qtile-extras/default.nix;
   quake3 = runTest ./quake3.nix;
   quicktun = runTest ./quicktun.nix;

nixos/tests/qtile-extras/add-startup-hook.patch

@@ -0,0 +1,22 @@
+--- a/config.py	2025-08-03 00:37:13.058374602 +0200
++++ b/config.py	2025-08-03 00:45:51.869382363 +0200
+@@ -24,10 +24,18 @@
+ # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ # SOFTWARE.
+ 
+-from libqtile import bar, layout, qtile, widget
++from libqtile import bar, layout, qtile, widget, hook
+ from libqtile.config import Click, Drag, Group, Key, Match, Screen
+ from libqtile.lazy import lazy
+ from libqtile.utils import guess_terminal
++from libqtile.log_utils import logger
++
++
++@hook.subscribe.startup
++def print_ready():
++    logger.warning("ready!") # warning to make it always visible
++
++
+ 
+ mod = "mod4"
+ terminal = guess_terminal()

nixos/tests/qtile-extras/config.nix

@@ -15,7 +15,10 @@ stdenvNoCC.mkDerivation {
     cp $src config.py
   '';
 
-  patches = [ ./add-widget.patch ];
+  patches = [
+    ./add-widget.patch
+    ./add-startup-hook.patch
+  ];
 
   dontUnpack = true;
   dontBuild = true;

nixos/tests/qtile-extras/default.nix

@@ -40,6 +40,8 @@
     };
 
   testScript = ''
+    from pathlib import Path
+
     with subtest("ensure x starts"):
         machine.wait_for_x()
         machine.wait_for_file("/home/alice/.Xauthority")
@@ -48,6 +50,13 @@
     with subtest("ensure client is available"):
         machine.succeed("qtile --version")
 
+    with subtest("Qtile signals that it is ready"):
+        qtile_logfile = Path("/home/alice/.local/share/qtile/qtile.log")
+
+        machine.succeed(f"mkdir -p {qtile_logfile.parent}")
+        machine.succeed(f"touch {qtile_logfile}")
+        machine.succeed(f"sh -c 'tail -f {qtile_logfile} | grep --line-buffered \'ready\' -m 1'")
+
     with subtest("ensure we can open a new terminal"):
         machine.send_key("meta_l-ret")
         machine.wait_for_window(r"alice.*?machine")

nixos/tests/qtile.nix

@@ -1,46 +0,0 @@
-{ lib, ... }:
-{
-  name = "qtile";
-
-  meta = {
-    maintainers = with lib.maintainers; [
-      sigmanificient
-      gurjaka
-    ];
-  };
-
-  nodes.machine =
-    {
-      pkgs,
-      lib,
-      ...
-    }:
-    {
-      imports = [
-        ./common/x11.nix
-        ./common/user-account.nix
-      ];
-      test-support.displayManager.auto.user = "alice";
-
-      services.xserver.windowManager.qtile.enable = true;
-
-      services.displayManager.defaultSession = lib.mkForce "qtile";
-
-      environment.systemPackages = [ pkgs.kitty ];
-    };
-
-  testScript = ''
-    with subtest("ensure x starts"):
-        machine.wait_for_x()
-        machine.wait_for_file("/home/alice/.Xauthority")
-        machine.succeed("xauth merge ~alice/.Xauthority")
-
-    with subtest("ensure client is available"):
-        machine.succeed("qtile --version")
-
-    with subtest("ensure we can open a new terminal"):
-        machine.send_key("meta_l-ret")
-        machine.wait_for_window(r"alice.*?machine")
-        machine.screenshot("terminal")
-  '';
-}

nixos/tests/qtile/add-startup-hook.patch

@@ -0,0 +1,22 @@
+--- a/config.py	2025-08-03 00:37:13.058374602 +0200
++++ b/config.py	2025-08-03 00:45:51.869382363 +0200
+@@ -24,10 +24,18 @@
+ # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ # SOFTWARE.
+ 
+-from libqtile import bar, layout, qtile, widget
++from libqtile import bar, layout, qtile, widget, hook
+ from libqtile.config import Click, Drag, Group, Key, Match, Screen
+ from libqtile.lazy import lazy
+ from libqtile.utils import guess_terminal
++from libqtile.log_utils import logger
++
++
++@hook.subscribe.startup
++def print_ready():
++    logger.warning("ready!") # warning to make it always visible
++
++
+ 
+ mod = "mod4"
+ terminal = guess_terminal()

nixos/tests/qtile/config.nix

@@ -0,0 +1,27 @@
+{
+  stdenvNoCC,
+  fetchurl,
+}:
+stdenvNoCC.mkDerivation {
+  name = "qtile-extras-config";
+  version = "0.0.1";
+
+  src = fetchurl {
+    url = "https://raw.githubusercontent.com/qtile/qtile/v0.28.1/libqtile/resources/default_config.py";
+    hash = "sha256-Y5W277CWVNSi4BdgEW/f7Px/MMjnN9W9TDqdOncVwPc=";
+  };
+
+  prePatch = ''
+    cp $src config.py
+  '';
+
+  patches = [ ./add-startup-hook.patch ];
+
+  dontUnpack = true;
+  dontBuild = true;
+
+  installPhase = ''
+    mkdir -p $out
+    cp config.py $out/config.py
+  '';
+}

nixos/tests/qtile/default.nix

@@ -0,0 +1,68 @@
+{ lib, ... }:
+{
+  name = "qtile";
+
+  meta = {
+    maintainers = with lib.maintainers; [
+      sigmanificient
+      gurjaka
+    ];
+  };
+
+  nodes.machine =
+    {
+      pkgs,
+      lib,
+      ...
+    }:
+    let
+      # We create a custom Qtile configuration file that adds a
+      # startup hook to qtile. This ensure we can reproducibly check
+      # when Qtile is truly ready to receive our inputs
+      config-deriv = pkgs.callPackage ./config.nix { };
+    in
+    {
+      imports = [
+        ../common/x11.nix
+        ../common/user-account.nix
+      ];
+      test-support.displayManager.auto.user = "alice";
+
+      services.xserver.windowManager.qtile = {
+        enable = true;
+        configFile = "${config-deriv}/config.py";
+        extraPackages = ps: [ ps.qtile-extras ];
+      };
+
+      services.displayManager.defaultSession = lib.mkForce "qtile";
+
+      environment.systemPackages = [
+        pkgs.kitty
+        pkgs.xorg.xwininfo
+      ];
+    };
+
+  testScript = ''
+    from pathlib import Path
+
+    with subtest("ensure x starts"):
+        machine.wait_for_x()
+        machine.wait_for_file("/home/alice/.Xauthority")
+        machine.succeed("xauth merge ~alice/.Xauthority")
+
+    with subtest("ensure client is available"):
+        machine.succeed("qtile --version")
+
+    with subtest("Qtile signals that it is ready"):
+        qtile_logfile = Path("/home/alice/.local/share/qtile/qtile.log")
+
+        machine.succeed(f"mkdir -p {qtile_logfile.parent}")
+        machine.succeed(f"touch {qtile_logfile}")
+        machine.succeed(f"sh -c 'tail -f {qtile_logfile} | grep --line-buffered \'ready\' -m 1'")
+
+    with subtest("ensure we can open a new terminal"):
+        machine.send_key("meta_l-ret")
+        machine.wait_for_window(r"alice.*?machine")
+        machine.screenshot("terminal")
+  '';
+}