def METHOD_NAME(self, mock_shutil_copy2):
    file_src = self.get_mock_file_base("does-not-exist.tar.gz", ".")
    raised = self.assertRaises(errors.SnapcraftSourceNotFoundError, file_src.pull)
    self.assertThat(
        str(raised), Contains("Failed to pull source: 'does-not-exist.tar.gz'")
    )