public void IfTooLong()
{
var veryLong = "very long";
Assert.Throws <DesignByContractViolationException>(
() => Fail.IfToLong(veryLong, 3, nameof(veryLong))
);
Fail.IfToLong(null, 300, "null");
Fail.IfToLong("aa", 300, "aa");
Fail.IfToLong("aa", 2, "aa");
}