New Post: FluentValidation: RuleSet unit testing

public static class ValidationTestExtension
{
    public static void ShouldHaveValidationErrorFor<T>
        (this IValidator<T> validator, string propertyName, T objectToTest,
        string ruleSet) where T : class
    {
        var results = validator.Validate(objectToTest, ruleSet: ruleSet);
        results.Errors.Any(e => e.PropertyName == propertyName).Should().Be(true);
    }

    public static void ShouldNotHaveValidationErrorFor<T>
        (this IValidator<T> validator, string propertyName, T objectToTest,
        string ruleSet) where T : class
    {
        var results = validator.Validate(objectToTest, ruleSet: ruleSet);
        results.Errors.Any(e => e.PropertyName == propertyName).Should().Be(false);
    }
}

var user = new User { Email = "" };
_validator.ShouldHaveValidationErrorFor("Email", user, "SignUpRuleSet");