public void RemovedValues(T[] items)
            {
                var list = new DoublyCircularLinkedList <T>(items);

                for (var i = 0; i < items.Length; i++)
                {
                    list.Remove(items[i]);
                    Assert.DoesNotContain(items[i], list); //"Should not contain item"
                }
            }
            public void AddRemoveValues(T[] items)
            {
                var list = new DoublyCircularLinkedList <T>(items);

                for (var i = 0; i < items.Length; i++)
                {
                    list.Add(items[i]);
                    list.Remove(items[i]);
                    list.Add(items[i]);
                    Assert.Contains(items[i], list); //"Should contain item."
                }
            }
            public void MultipleValues(T[] items, int times)
            {
                var list = new DoublyCircularLinkedList <T>(items);

                for (var i = 0; i < times; i++)
                {
                    list.Add(items[items.Length / 2]);
                }

                for (var i = 0; i < times + 1; i++)
                {
                    Assert.Contains(items[items.Length / 2], list); //"Should contain item."
                    list.Remove(items[items.Length / 2]);
                }
                Assert.DoesNotContain(items[items.Length / 2], list); //"Should not contain item"
            }