public void ShouldNotAddIfAlreadyExists()
            {
                // ReSharper disable once UseObjectOrCollectionInitializer
                var set = new ConcurrentRoundRobinSet <int> {
                    0, 1, 2, 3
                };

                set.Add(0);
                set.Add(1);
                set.Add(2);
                set.Add(3);
                set.Count.Should().Be(4);
                set.Should().ContainInOrder(0, 1, 2, 3);
            }
            public void ShouldClear()
            {
                // Given
                var set = new ConcurrentRoundRobinSet <int> {
                    0, 1, 2, 3
                };
                int ignored;

                set.TryNext(out ignored);
                set.Index.Should().Be(1);

                // When
                set.Clear();

                // Then
                set.Should().BeEmpty();
                set.Index.Should().Be(0);
            }