public void FailTestTakeFirst2()
        {
            var sequence = new[] { 1 };

            sequence.TakeFirst(2).ToList();
        }
        public void TestTakeFirst1()
        {
            var sequence = new[] {1, 2, 3, 4, 5, 6};

            var items = sequence.TakeFirst(2).ToList();
            Assert.AreEqual(2, items.Count());
            Assert.AreEqual(1, items[0]);
            Assert.AreEqual(2, items[1]);
        }