public void ContainsAllTestNullCheck()
        {
            // ReSharper disable once ReturnValueOfPureMethodIsNotUsed
            // ReSharper disable once AssignNullToNotNullAttribute
            Action test = () => IEnumerableTEx.ContainsAll(null, new Object(), new Object());

            test.ShouldThrow <ArgumentNullException>();
        }
        public void ContainsAllTest1NullCheck()
        {
            // ReSharper disable once AssignNullToNotNullAttribute
            // ReSharper disable once ReturnValueOfPureMethodIsNotUsed
            Action test = () => IEnumerableTEx.ContainsAll(null, new List <String>());

            Assert.Throws <ArgumentNullException>(test);
        }