public void AddLessThanValidationPredicate_WhenArgumentIsDateTime()
{
// Arrange.
ValidatableArgument<DateTime> argument = new ValidatableArgument<DateTime>("argument", DateTime.Now);
// Act.
argument.IsLessThan(DateTime.Now);
// Assert.
Assert.AreEqual(1, argument.ValidationPredicates.Count());
Assert.IsInstanceOfType(argument.ValidationPredicates.First(), typeof(LessThanValidationPredicate<DateTime>));
}