def test_positional_metadata_getter_set_column_array(self):
        length = 8
        obj = self._positional_metadata_constructor_(
            length, positional_metadata={'foo': range(length)})

        # array-like objects will fail if wrong size.
        for array_like in (np.array(range(1-length)), range(length-1),
                           np.array(range(length+1)), range(length+1)):
            with self.assertRaisesRegex(ValueError,
                                        "Length of values does not match "
                                        "length of index"):
                obj.positional_metadata['bar'] = array_like
dataset/ETHPy150Open biocore/scikit-bio/skbio/metadata/_testing.py/PositionalMetadataMixinTests.test_positional_metadata_getter_set_column_array/swapped operands of `-`