def METHOD_NAME(self):
    """Test output is a tuple of cubes"""
    cubelist = [self.first_cube, self.second_cube, self.third_cube]
    result = generate_optical_flow_components(
        cubelist, self.ofc_box_size, self.iterations
    )
    for cube in result:
        self.assertIsInstance(cube, iris.cube.Cube)
        self.assertAlmostEqual(cube.coord("time").points[0], self.expected_time)