public void ThrowArgumentException_WhenTheFirstMachingValidationRuleIsEqual()
{
// Arrange.
IValidatableArgument<string> argument = new ValidatableArgument<string>("argument", "asdf");
argument.IsNotEqual("asdf").IsEqual("asdf").IsNotNull();
// Act & Assert.
Ensure.ArgumentExceptionIsThrown(
() =>
{
argument.Throw();
}, "argument");
}