import warnings with warnings.catch_warnings(record=True) as w: # Arrange: cause all warnings to always be triggered warnings.simplefilter("always") # Act: trigger a warning with Qt5 from PIL import ImageQt def test_deprecated(): # Assert if ImageQt.qt_version in ("5", "side2"): assert len(w) == 1 assert issubclass(w[0].category, DeprecationWarning) assert "deprecated" in str(w[0].message) else: assert len(w) == 0