public void SynchronisedDoubleEndedQueueContainsReturnsFalseIfItemIsNotInDequeue()
        {
            var items = new[] { 1, 2, 3, 4, 5, 6, 7, 8 };

            var deque = new SynchronisedDeque <int>(items);

            Assert.IsFalse(deque.Contains(9));
        }