def METHOD_NAME(self):
    # Check the expansion of small chunks, (with a known size limit).
    given_shapes_and_resulting_chunks = [
        ((1, 100, 100), (16, 100, 100), (16, 100, 100)),
        ((1, 100, 100), (5000, 100, 100), (1667, 100, 100)),
        ((3, 300, 200), (10000, 3000, 2000), (3, 1500, 2000)),
        ((3, 300, 200), (10000, 300, 2000), (27, 300, 2000)),
        ((3, 300, 200), (8, 300, 2000), (8, 300, 2000)),
        ((3, 300, 200), (117, 300, 1000), (39, 300, 1000)),
    ]
    err_fmt = "Result of optimising shape={};chunks={} was {}, expected {}"
    for shape, fullshape, expected in given_shapes_and_resulting_chunks:
        chunks = _optimum_chunksize(
            chunks=shape, shape=fullshape, limit=self.FIXED_CHUNKSIZE_LIMIT
        )
        msg = err_fmt.format(fullshape, shape, chunks, expected)
        self.assertEqual(chunks, expected, msg)