def test_modules_importable_as_side_effect(self, pytester: Pytester) -> None:
        """In import-modes `prepend` and `append`, we are able to import modules from folders
        containing conftest.py files due to the side effect of changing sys.path."""
        self.setup_conftest_and_foo(pytester)
        result = pytester.runpytest("-v", "--import-mode=prepend")
        result.stdout.fnmatch_lines(["* 1 passed in *"])
In import-modes `prepend` and `append`, we are able to import modules from folders
        containing conftest.py files due to the side effect of changing sys.path.
testing/test_collection.py