public void TestRequireContainsElement()
{
Assert.Throws <ArgumentException>(() => ArgumentValidation.RequireContainsElement <IEnumerable <string> >(null, "A"));
Assert.Throws <ArgumentException>(() => Array.Empty <string>().RequireContainsElement("A"));
Assert.DoesNotThrow(() => new[] { 1, 2, 3 }.RequireContainsElement("A"));
}
