def METHOD_NAME(self):
    with testing_utils.tempdir() as tmpdir:
        import gzip
        fname = os.path.join(tmpdir, "test.txt.gz")
        with gzip.GzipFile(fname, mode="w") as f:
            f.write("This is a test\n".encode("utf-8"))
        build_data.ungzip(tmpdir, "test.txt.gz")
        out_fn = os.path.join(tmpdir, "test.txt")
        assert os.path.exists(out_fn)
        assert not os.path.exists(fname)
        with open(out_fn) as f:
            assert f.read() == "This is a test\n"