def test_oid_write_once(self):
t = Todo('some text', oid=None)
assert not t.oid
t.oid = 5
assert t.oid == 5
with pytest.raises(base.ReadOnlyError):
t.oid = 6
def test_oid_readonly(self):
t = Todo('some text', oid=4)
assert t.oid == 4
with pytest.raises(base.ReadOnlyError):
t.oid = 5