def make_test_files(self) -> None:
        """Create a simple file representing a method with two tests."""
        self.make_file("testsuite.py", """\
            def timestwo(x):
                return x*2

            def test_multiply_zero():
                assert timestwo(0) == 0

            def test_multiply_six():
                assert timestwo(6) == 12
            """)
Create a simple file representing a method with two tests.
tests/test_api.py