public void Should_be_valid_when_value_is_greater_using_instance_property()
        {
            var validator = new GreaterThanValidator<Person, int>(p => p.Age);

            var person = new Person {Age = 18};
            Assert.That(validator.Validate(person, 21), Is.True);
        }
        public void Should_be_invalid_when_value_is_lower_using_instance_property()
        {
            var validator = new GreaterThanValidator <Person, int>(p => p.Age);

            var person = new Person {
                Age = 18
            };

            Assert.That(validator.Validate(person, 16), Is.False);
        }
        public void Should_be_valid_when_value_is_greater()
        {
            var validator = new GreaterThanValidator<Person, int>(18);

            Assert.That(validator.Validate(null, 21), Is.True);
        }
        public void Should_be_invalid_when_value_is_lower()
        {
            var validator = new GreaterThanValidator<Person, int>(18);

            Assert.That(validator.Validate(null, 16), Is.False);
        }
        public void Should_be_invalid_when_value_is_lower()
        {
            var validator = new GreaterThanValidator <Person, int>(18);

            Assert.That(validator.Validate(null, 16), Is.False);
        }
        public void Should_be_valid_when_value_is_greater()
        {
            var validator = new GreaterThanValidator <Person, int>(18);

            Assert.That(validator.Validate(null, 21), Is.True);
        }