Method test_factorize_multiindex_empty

pandas/tests/test_algos.py:585–593

(self)

        tm.assert_index_equal(result, expected, exact=True)

    def test_factorize_multiindex_empty(self):
        # GH#57517
        mi = MultiIndex.from_product(
            [Index([], name="a", dtype=object), Index([], name="i", dtype="f4")]
        )
        codes, uniques = mi.factorize()
        exp_codes = np.array([], dtype=np.intp)
        tm.assert_numpy_array_equal(codes, exp_codes)
        tm.assert_index_equal(uniques, mi[:0])

    def test_dtype_preservation(self, any_numpy_dtype):
        # GH 15442