public void HeadTest()
        {
            const string data  = "One Two Three One Three";
            var          queue = data.Split().Aggregate(HoodMelvilleQueue <string> .Empty, HoodMelvilleQueue <string> .Snoc);
            var          head  = HoodMelvilleQueue <string> .Head(queue);

            Assert.AreEqual("One", head);
        }
        public void PushPopTest()
        {
            const string data  = "One Two Three One Three";
            var          queue = data.Split().Aggregate(HoodMelvilleQueue <string> .Empty, HoodMelvilleQueue <string> .Snoc);

            foreach (var expected in data.Split())
            {
                var actual = HoodMelvilleQueue <string> .Head(queue);

                Assert.AreEqual(expected, actual);
                queue = HoodMelvilleQueue <string> .Tail(queue);
            }

            Assert.IsTrue(HoodMelvilleQueue <string> .IsEmpty(queue));
        }
        public void EmptyHeadTest()
        {
            var queue = HoodMelvilleQueue <string> .Empty;

            AssertThrows <ArgumentNullException>(() => HoodMelvilleQueue <string> .Head(queue));
        }