Possible fix for mate's window switcher.

internal/atspi/window_switcher_native_test.go

@@ -0,0 +1,102 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package atspi
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestNativeMateWindowSwitcherOutsideForeground(t *testing.T) {
+	if os.Getenv("CTHULHU_NATIVE_WINDOW_SWITCHER") != "1" {
+		t.Skip("requires private Xorg/AT-SPI session")
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+	defer cancel()
+	adapter := New()
+	if err := adapter.Start(ctx); err != nil {
+		t.Fatal(err)
+	}
+	defer adapter.Stop(context.Background())
+	start := func(name string) (io.WriteCloser, string) {
+		command := exec.CommandContext(ctx, "/usr/bin/python3", "../../tests/gtk_window_switcher.py", name)
+		input, err := command.StdinPipe()
+		if err != nil {
+			t.Fatal(err)
+		}
+		output, err := command.StdoutPipe()
+		if err != nil {
+			t.Fatal(err)
+		}
+		command.Stderr = os.Stderr
+		if err := command.Start(); err != nil {
+			t.Fatal(err)
+		}
+		t.Cleanup(func() { input.Close(); command.Process.Kill(); command.Wait() })
+		line, err := bufio.NewReader(output).ReadString('\n')
+		fields := strings.Fields(line)
+		if err != nil || len(fields) != 2 || fields[0] != "ready" {
+			t.Fatalf("fixture readiness: %q, %v", line, err)
+		}
+		return input, fields[1]
+	}
+	switcher, _ := start("marco")
+	foreground, xid := start("editor")
+	if _, err := adapter.CaptureDesktop(ctx); err != nil {
+		t.Fatal(err)
+	}
+	if output, err := exec.CommandContext(ctx, "xdotool", "windowfocus", "--sync", xid).CombinedOutput(); err != nil {
+		t.Fatalf("focus: %s, %v", output, err)
+	}
+	wait := func(eventType, title string, switcher bool) Event {
+		t.Helper()
+		var last Event
+		count := 0
+		for {
+			select {
+			case event := <-adapter.Events():
+				last = event
+				count++
+				if event.Type == eventType && (event.Source.Name == title || event.Payload == title) {
+					if IsWindowSwitcherSelection(event) != switcher {
+						t.Fatalf("switcher classification: %+v", event)
+					}
+					return event
+				}
+			case <-ctx.Done():
+				t.Fatalf("missing %s %q; background-filtered=%d received=%d last=%+v", eventType, title, adapter.backgroundEventsFiltered.Load(), count, last)
+			}
+		}
+	}
+	fmt.Fprintln(foreground, "select Foreground ready")
+	owned := wait(TextInsertedEvent, "Foreground ready", false)
+	if owned.ForegroundMismatch || !owned.Foreground.Client.Known {
+		t.Fatalf("fixture has no correlated foreground: %+v", owned)
+	}
+	for _, title := range []string{"Editor", "Terminal", "Editor"} {
+		fmt.Fprintln(switcher, "select "+title)
+		event := wait(TextInsertedEvent, title, true)
+		if !event.ForegroundMismatch || event.Foreground != owned.Foreground || event.Source.Focused {
+			t.Fatalf("switcher acquired foreground/native focus: %+v", event)
+		}
+	}
+	fmt.Fprintln(switcher, "showing")
+	wait(ShowingStateEvent, "Editor", true)
+	// The provider stays separate from the old foreground after the popup
+	// disappears. Ordinary application events still use native correlation.
+	fmt.Fprintln(switcher, "hide")
+	fmt.Fprintln(foreground, "select Foreground retained")
+	retained := wait(TextInsertedEvent, "Foreground retained", false)
+	if retained.ForegroundMismatch || retained.Window != owned.Window {
+		t.Fatalf("switcher changed foreground ownership: %+v", retained)
+	}
+}