def test_invalid_scalar_index(adata, index):
    # https://github.com/theislab/anndata/issues/619
    with pytest.raises(IndexError, match=r".*index.* out of range\."):
        _ = adata[index]
def test_equal_to():
    """Equal to y."""
    p = are.equal_to(1)
    ps = [p(x) for x in range(1, 6)]
    assert ps == [True, False, False, False, False]