type-ignore in error-message test

testing/python/raises.py

@@ -21,7 +21,9 @@ class TestRaises:
 
     def test_raises_does_not_allow_none(self):
         with pytest.raises(ValueError, match="Expected an exception type or"):
-            pytest.raises(expected_exception=None)
+            # We're testing that this invalid usage gives a helpful error,
+            # so we can ignore Mypy telling us that None is invalid.
+            pytest.raises(expected_exception=None)  # type: ignore
 
     def test_raises_does_not_allow_empty_tuple(self):
         with pytest.raises(ValueError, match="Expected an exception type or"):