System.Reactive.EventStreamSpec.WhenUserLoginFailsTooFast_ThenLockUserAccount C# (CSharp) Method

        public void WhenUserLoginFailsTooFast_ThenLockUserAccount()
        {
            var seconds = TimeSpan.FromSeconds(1).Ticks;
            var events = new EventStream();

            // Here we use the test scheduler to simulate time passing by
            // because we have a dependency on time because of the Buffer
            // method.
            var scheduler = new TestScheduler();
            var observable = scheduler.CreateColdObservable(
                // Two users attempt to log in, 4 times in a row
                new Recorded<Notification<LoginFailure>>(10 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 1 })),
                new Recorded<Notification<LoginFailure>>(10 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 2 })),
                new Recorded<Notification<LoginFailure>>(20 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 1 })),
                new Recorded<Notification<LoginFailure>>(20 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 2 })),
                new Recorded<Notification<LoginFailure>>(30 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 1 })),
                new Recorded<Notification<LoginFailure>>(30 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 2 })),
                new Recorded<Notification<LoginFailure>>(40 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 1 })),
                new Recorded<Notification<LoginFailure>>(40 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 2 })),

                // User 2 attems one more time within the 1' window
                new Recorded<Notification<LoginFailure>>(45 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 2 })),

                // User 1 pulls out the paper where he wrote his pwd ;), so he takes longer
                new Recorded<Notification<LoginFailure>>(75 * seconds, Notification.CreateOnNext(new LoginFailure { UserId = 1 }))
            );

            // This subscription bridges the scheduler-driven 
            // observable with our event stream, causing us 
            // to publish events as they are "raised" by the 
            // test scheduler.
            observable.Subscribe(failure => events.Push(failure));

            var query = events.Of<LoginFailure>()
                // Sliding windows 1' long, every 10''
                .Buffer(TimeSpan.FromMinutes(1), TimeSpan.FromSeconds(10), scheduler)
                // From all failure values
                .SelectMany(failures => failures
                    // Group the failures by user
                    .GroupBy(failure => failure.UserId)
                    // Only grab those failures with more than 5 in the 1' window
                    .Where(group => group.Count() >= 5)
                    // Return the user id that failed to log in
                    .Select(group => group.Key));

            var blocked = new List<int>();

            using (var subscription = query.Subscribe(userId => blocked.Add(userId)))
            {
                // Here we could advance the scheduler half way and test intermediate 
                // state if needed. We go all the way past the end of our login failures.
                scheduler.AdvanceTo(100 * seconds);
            }

            // We should have only user # 2 in the list.
            Assert.False(blocked.Contains(1));
            Assert.True(blocked.Contains(2));
        }