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

                list.Clear();
                Assert.Empty(list); //"Should be equal to 0."
            }
            public void ClearEmptyList()
            {
                var list = new DoublyCircularLinkedList <T>();

                Assert.Empty(list); //"Should be equal to 0"
                list.Clear();
                Assert.Empty(list); //"Should be equal to 0."
            }
            public void ClearMultipleTimesNonEmptyList(T[] items, int times)
            {
                var list = new DoublyCircularLinkedList <T>(items);

                for (var i = 0; i < times; i++)
                {
                    list.Clear();
                    Assert.Empty(list); //"Should be equal to 0."
                }
            }