def test_negative_scalar_index(adata, index: int, obs: bool):
    pos_index = index + (adata.n_obs if obs else adata.n_vars)

    if obs:
        adata_pos_subset = adata[pos_index]
        adata_neg_subset = adata[index]
    else:
        adata_pos_subset = adata[:, pos_index]
        adata_neg_subset = adata[:, index]

    np.testing.assert_array_equal(
        adata_pos_subset.obs_names, adata_neg_subset.obs_names
    )
    np.testing.assert_array_equal(
        adata_pos_subset.var_names, adata_neg_subset.var_names
    )
def test_invalid_isointerval_error():
    try:
        inputs.iso8601interval('2013-01-01/blah')
    except ValueError as error:
        assert_equal(
            str(error),
            "Invalid argument: 2013-01-01/blah. argument must be a valid ISO8601 "
            "date/time interval.",
        )
        return
    assert False, 'Should raise a ValueError'