public void Should_validate_length()
    {
        var ok1 = new Model {
            MyProperty = null
        };
        var ok2 = new Model {
            MyProperty = ""
        };
        var ok3 = new Model {
            MyProperty = "55555"
        };
        var fail = new Model {
            MyProperty = "1"
        };
        var v = new ModelValidator();

        v.ValidateAndThrow(ok1);
        v.ValidateAndThrow(ok2);
        v.ValidateAndThrow(ok3);
        Should.Throw <ValidationException> (() => v.ValidateAndThrow(fail));
    }