tests: Add overlay cursor test

This test checks a particular issue, where a pointer moved in a way
resulting in the cursor position not changing, then moving again,
changing the cursor position, not damaging the area of the original
position, causing the cursor to get "stuck" until damaged due to some
other reason.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4331>

src/tests/cursor-overlay-tests.c

@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2025 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "config.h"
+
+#include "backends/meta-backend-private.h"
+#include "backends/meta-renderer.h"
+#include "tests/meta-test/meta-context-test.h"
+#include "tests/meta-test/meta-test-monitor.h"
+#include "tests/meta-ref-test.h"
+#include "tests/meta-test-utils.h"
+
+static MetaContext *test_context;
+
+static ClutterStageView *
+get_view (void)
+{
+  MetaBackend *backend = meta_context_get_backend (test_context);
+  MetaRenderer *renderer = meta_backend_get_renderer (backend);
+  GList *views;
+
+  views = meta_renderer_get_views (renderer);
+  g_assert_cmpuint (g_list_length (views), ==, 1);
+
+  return CLUTTER_STAGE_VIEW (views->data);
+}
+
+static void
+meta_test_cursor_overlay_damage (void)
+{
+  MetaBackend *backend = meta_context_get_backend (test_context);
+  ClutterSeat *seat = meta_backend_get_default_seat (backend);
+  g_autoptr (MetaVirtualMonitor) test_monitor = NULL;
+  g_autoptr (ClutterVirtualInputDevice) virtual_pointer = NULL;
+  g_autoptr (GError) error = NULL;
+
+  test_monitor = meta_create_test_monitor (test_context, 100, 100, 60.0);
+  g_assert_nonnull (test_monitor);
+  g_assert_no_error (error);
+
+  virtual_pointer = clutter_seat_create_virtual_device (seat,
+                                                        CLUTTER_POINTER_DEVICE);
+  clutter_virtual_input_device_notify_absolute_motion (virtual_pointer,
+                                                       g_get_monotonic_time (),
+                                                       50.0f, 50.0f);
+
+  meta_flush_input (test_context);
+  meta_wait_for_paint (test_context);
+
+  clutter_virtual_input_device_notify_absolute_motion (virtual_pointer,
+                                                       g_get_monotonic_time (),
+                                                       50.0f, 50.0f);
+
+  meta_flush_input (test_context);
+  meta_wait_for_paint (test_context);
+
+  clutter_virtual_input_device_notify_absolute_motion (virtual_pointer,
+                                                       g_get_monotonic_time (),
+                                                       75.0f, 75.0f);
+
+  meta_flush_input (test_context);
+
+  meta_ref_test_verify_view_undamaged (get_view (),
+                                       g_test_get_path (), 0,
+                                       meta_ref_test_determine_ref_test_flag ());
+}
+
+static void
+init_tests (void)
+{
+  g_test_add_func ("/backends/cursor-overlay/damage",
+                   meta_test_cursor_overlay_damage);
+}
+
+int
+main (int    argc,
+      char **argv)
+{
+  g_autoptr (MetaContext) context = NULL;
+
+  context = meta_create_test_context (META_CONTEXT_TEST_TYPE_HEADLESS,
+                                      META_CONTEXT_TEST_FLAG_NO_X11);
+  g_assert_true (meta_context_configure (context, &argc, &argv, NULL));
+  meta_context_test_set_background_color (META_CONTEXT_TEST (context),
+                                          COGL_COLOR_INIT (255, 255, 255, 255));
+
+  test_context = context;
+
+  init_tests ();
+
+  return meta_context_test_run_tests (META_CONTEXT_TEST (context),
+                                      META_TEST_RUN_FLAG_NONE);
+}

src/tests/meson.build

@@ -512,6 +512,14 @@ test_cases += [
       'meta-thread-impl-test.h',
     ],
   },
+  {
+    'name': 'cursor-overlay-tests',
+    'suite': 'backends/native',
+    'sources': [
+      'cursor-overlay-tests.c',
+      wayland_test_utils,
+    ],
+  },
   {
     'name': 'cursor-tests',
     'suite': 'backends/native',