public void AddGreaterThanValidationPredicate_WhenArgumentIsDecimal()
{
// Arrange.
ValidatableArgument<decimal> argument = new ValidatableArgument<decimal>("argument", 3);
// Act.
argument.IsGreaterThan(5);
// Assert.
Assert.AreEqual(1, argument.ValidationPredicates.Count());
Assert.IsInstanceOfType(argument.ValidationPredicates.First(), typeof(GreaterThanValidationPredicate<decimal>));
}