tests: Skip GUI tests if key dependencies are missing.

Ignore GUI tests if DISPLAY is not set or PyQt is not available.

Signed-off-by: Chris PeBenito <chpebeni@linux.microsoft.com>

tests/gui/conftest.py

@@ -0,0 +1,31 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+import os
+import pathlib
+import pytest
+
+try:
+    import PyQt6
+    have_pyqt6 = True
+except ImportError:
+    have_pyqt6 = False
+
+try:
+    import pytestqt
+    have_pqtestqt = True
+except ImportError:
+    have_pqtestqt = False
+
+
+def pytest_ignore_collect(collection_path: pathlib.Path, path,
+                          config: pytest.Config) -> bool | None:
+
+    """Ignore GUI tests if DISPLAY is not set or PyQt is not available."""
+
+    xdisp = bool(os.getenv("DISPLAY"))
+
+    # Return True to prevent considering this path for collection.
+    if all((xdisp, have_pyqt6, have_pqtestqt)):
+        return False
+
+    return True