def test_layers_view():
    X = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
    L = np.array([[10, 11, 12], [13, 14, 15], [16, 17, 18]])
    real_adata = ad.AnnData(X)
    real_adata.layers["L"] = L
    view_adata = real_adata[1:, 1:]
    real_hash = joblib.hash(real_adata)
    view_hash = joblib.hash(view_adata)

    assert view_adata.is_view

    with pytest.raises(ValueError):
        view_adata.layers["L2"] = L + 2

    assert view_adata.is_view  # Failing to set layer item makes adata not view
    assert real_hash == joblib.hash(real_adata)
    assert view_hash == joblib.hash(view_adata)

    view_adata.layers["L2"] = L[1:, 1:] + 2

    assert not view_adata.is_view
    assert real_hash == joblib.hash(real_adata)
    assert view_hash != joblib.hash(view_adata)
def _parse_filter():
        op = pyparsing.oneOf('! & |')
        lpar  = pyparsing.Literal('(').suppress()
        rpar  = pyparsing.Literal(')').suppress()

        k = pyparsing.Word(pyparsing.alphanums)
        # NOTE: We may need to expand on this list, but as this is not a real
        # LDAP server we should be OK.
        # Value to contain:
        #   numbers, upper/lower case letters, astrisk, at symbol, minus, full
        #   stop, backslash or a space
        v = pyparsing.Word(pyparsing.alphanums + "-*@.\\ äöü")
        rel = pyparsing.oneOf("= ~= >= <=")

        expr = pyparsing.Forward()
        atom = pyparsing.Group(lpar + op + expr + rpar) \
                            | pyparsing.Combine(lpar + k + rel + v + rpar)
        expr << atom + pyparsing.ZeroOrMore( expr )

        return expr