    def test_if_the_most_relevant_error_is_allOf_it_is_traversed(self):
        """
        Now, if the error is allOf, we traverse but select the *most* relevant
        error from the context, because all schemas here must match anyways.
        """

        schema = {
            "properties": {
                "foo": {
                    "allOf": [
                        {"type": "string"},
                        {"properties": {"bar": {"type": "array"}}},
                    ],
                },
            },
        }
        best = self.best_match_of(instance={"foo": {"bar": 12}}, schema=schema)
        self.assertEqual(best.validator_value, "string")
Now, if the error is allOf, we traverse but select the *most* relevant
error from the context, because all schemas here must match anyways.
jsonschema/tests/test_exceptions.py