public void ReplacePropertyValidator_should_replace_property()
        {
            validator.RuleFor(x => x.Surname).Length(5, 10).WithMessage("foo");

            var result = validator.Validate(new Person {
                Surname = "Matthew Leibowitz"
            });

            result.Errors.Single().ErrorMessage.ShouldEqual("foo");

            validator.ReplaceRule(x => x.Surname, new LengthValidator(10, 20));

            result = validator.Validate(new Person {
                Surname = "Matthew Leibowitz"
            });
            Assert.Equal(0, result.Errors.Count);
        }