public void can_check_no_items_match() { var pass = Check.That(subject).container[Should.HaveNone(o => o as string == "four", "four found!")]; var fail = Check.That(subject).container[Should.HaveNone(o => o as string == "three", "three found!")]; Assert.That(pass.Success, Is.True, pass.Reason); Assert.That(fail.Success, Is.False); Assert.That(fail.Reasons, Contains.Item("Outer.container three found!")); }