add pytest fixture to quit Qt after suite has run

Author: jsheunis

datalad_gooey/tests/test_utils.py

@@ -0,0 +1,9 @@
+import pytest
+
+@pytest.fixture(autouse=True, scope="session")
+def quitQt():
+    """Ensure that Qt quits properly at the end of the test suite.
+    See: https://github.com/The-Compiler/pytest-xvfb/issues/11
+    """
+    from PySide6.QtWidgets import QApplication
+    QApplication.quit()