public override async Task CanAcquireResourceAsync_QueuesAndGrabsNewest()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(2, QueueProcessingOrder.NewestFirst, 3,
                                                                                           TimeSpan.FromMinutes(0), 2, autoReplenishment: false));

            var lease = await limiter.WaitAndAcquireAsync(2);

            Assert.True(lease.IsAcquired);

            var wait1 = limiter.WaitAndAcquireAsync(2);
            var wait2 = limiter.WaitAndAcquireAsync();

            Assert.False(wait1.IsCompleted);
            Assert.False(wait2.IsCompleted);

            lease.Dispose();
            Assert.True(limiter.TryReplenish());
            Assert.False(wait2.IsCompleted);

            Assert.True(limiter.TryReplenish());
            // second queued item completes first with NewestFirst
            lease = await wait2;
            Assert.True(lease.IsAcquired);
            Assert.False(wait1.IsCompleted);

            lease.Dispose();
            Assert.Equal(1, limiter.GetAvailablePermits());
            Assert.True(limiter.TryReplenish());
            Assert.True(limiter.TryReplenish());

            lease = await wait1;
            Assert.True(lease.IsAcquired);
        }
        public override async Task DropsMultipleOldestWhenQueuingMoreThanLimit_NewestFirst()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(2, QueueProcessingOrder.NewestFirst, 2,
                                                                                           TimeSpan.Zero, 2, autoReplenishment: false));
            var lease = limiter.Acquire(2);

            Assert.True(lease.IsAcquired);
            var wait = limiter.WaitAndAcquireAsync(1);

            Assert.False(wait.IsCompleted);

            var wait2 = limiter.WaitAndAcquireAsync(1);

            Assert.False(wait2.IsCompleted);

            var wait3  = limiter.WaitAndAcquireAsync(2);
            var lease1 = await wait;
            var lease2 = await wait2;

            Assert.False(lease1.IsAcquired);
            Assert.False(lease2.IsAcquired);
            Assert.False(wait3.IsCompleted);

            limiter.TryReplenish();
            limiter.TryReplenish();

            lease = await wait3;
            Assert.True(lease.IsAcquired);
        }
        public override async Task DisposeAsyncReleasesQueuedAcquires()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(1, QueueProcessingOrder.OldestFirst, 3,
                                                                                           TimeSpan.Zero, 2, autoReplenishment: false));
            var lease = limiter.Acquire(1);
            var wait1 = limiter.WaitAndAcquireAsync(1);
            var wait2 = limiter.WaitAndAcquireAsync(1);
            var wait3 = limiter.WaitAndAcquireAsync(1);

            Assert.False(wait1.IsCompleted);
            Assert.False(wait2.IsCompleted);
            Assert.False(wait3.IsCompleted);

            await limiter.DisposeAsync();

            lease = await wait1;
            Assert.False(lease.IsAcquired);
            lease = await wait2;
            Assert.False(lease.IsAcquired);
            lease = await wait3;
            Assert.False(lease.IsAcquired);

            // Throws after disposal
            Assert.Throws <ObjectDisposedException>(() => limiter.Acquire(1));
            await Assert.ThrowsAsync <ObjectDisposedException>(() => limiter.WaitAndAcquireAsync(1).AsTask());
        }
        public void ReplenishingRateLimiterPropertiesHaveCorrectValues()
        {
            var replenishPeriod = TimeSpan.FromMinutes(1);
            using ReplenishingRateLimiter limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 1,
                QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
                QueueLimit = 2,
                Window = replenishPeriod,
                SegmentsPerWindow = 1,
                AutoReplenishment = true
            });
            Assert.True(limiter.IsAutoReplenishing);
            Assert.Equal(replenishPeriod, limiter.ReplenishmentPeriod);

            replenishPeriod = TimeSpan.FromSeconds(2);
            using ReplenishingRateLimiter limiter2 = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 1,
                QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
                QueueLimit = 2,
                Window = replenishPeriod,
                SegmentsPerWindow = 1,
                AutoReplenishment = false
            });
            Assert.False(limiter2.IsAutoReplenishing);
            Assert.Equal(replenishPeriod, limiter2.ReplenishmentPeriod);
        }
        public override async Task CanDequeueMultipleResourcesAtOnce()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(2, QueueProcessingOrder.OldestFirst, 4,
                                                                                           TimeSpan.Zero, 2, autoReplenishment: false));

            using var lease = await limiter.WaitAndAcquireAsync(2);

            Assert.True(lease.IsAcquired);

            var wait1 = limiter.WaitAndAcquireAsync(1);
            var wait2 = limiter.WaitAndAcquireAsync(1);

            Assert.False(wait1.IsCompleted);
            Assert.False(wait2.IsCompleted);

            lease.Dispose();
            Assert.True(limiter.TryReplenish());
            Assert.True(limiter.TryReplenish());

            var lease1 = await wait1;
            var lease2 = await wait2;

            Assert.True(lease1.IsAcquired);
            Assert.True(lease2.IsAcquired);
        }
        public override async Task CannotAcquireResourcesWithWaitAndAcquireAsyncWithQueuedItemsIfOldestFirst()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(3, QueueProcessingOrder.OldestFirst, 5,
                                                                                           TimeSpan.Zero, 2, autoReplenishment: false));

            var lease = limiter.Acquire(3);

            Assert.True(lease.IsAcquired);

            var wait  = limiter.WaitAndAcquireAsync(2);
            var wait2 = limiter.WaitAndAcquireAsync(2);

            Assert.False(wait.IsCompleted);
            Assert.False(wait2.IsCompleted);

            limiter.TryReplenish();

            Assert.False(wait.IsCompleted);
            Assert.False(wait2.IsCompleted);

            limiter.TryReplenish();

            lease = await wait;
            Assert.True(lease.IsAcquired);

            limiter.TryReplenish();
            limiter.TryReplenish();

            lease = await wait2;
            Assert.True(lease.IsAcquired);
        }
        public override async Task CancelUpdatesQueueLimit()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 2,
                QueueProcessingOrder = QueueProcessingOrder.NewestFirst,
                QueueLimit = 1,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 2,
                AutoReplenishment = false
            });
            var lease = limiter.AttemptAcquire(2);
            Assert.True(lease.IsAcquired);

            var cts = new CancellationTokenSource();
            var wait = limiter.AcquireAsync(1, cts.Token);

            cts.Cancel();
            var ex = await Assert.ThrowsAsync<TaskCanceledException>(() => wait.AsTask());
            Assert.Equal(cts.Token, ex.CancellationToken);

            wait = limiter.AcquireAsync(1);
            Assert.False(wait.IsCompleted);

            limiter.TryReplenish();
            limiter.TryReplenish();

            lease = await wait;
            Assert.True(lease.IsAcquired);
            Assert.Equal(1, limiter.GetStatistics().CurrentAvailablePermits);
        }
        public override void ThrowsWhenAcquiringLessThanZero()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(1, QueueProcessingOrder.NewestFirst, 1,
                                                                                           TimeSpan.Zero, 1, autoReplenishment: false));

            Assert.Throws <ArgumentOutOfRangeException>(() => limiter.Acquire(-1));
        }
        public override async Task LargeAcquiresAndQueuesDoNotIntegerOverflow()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = int.MaxValue,
                QueueProcessingOrder = QueueProcessingOrder.NewestFirst,
                QueueLimit = int.MaxValue,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 2,
                AutoReplenishment = false
            });
            var lease = limiter.AttemptAcquire(int.MaxValue);
            Assert.True(lease.IsAcquired);

            // Fill queue
            var wait = limiter.AcquireAsync(3);
            Assert.False(wait.IsCompleted);

            var wait2 = limiter.AcquireAsync(int.MaxValue);
            Assert.False(wait2.IsCompleted);

            var lease1 = await wait;
            Assert.False(lease1.IsAcquired);

            limiter.TryReplenish();
            limiter.TryReplenish();
            var lease2 = await wait2;
            Assert.True(lease2.IsAcquired);
        }
        public override async Task CanDequeueMultipleResourcesAtOnce()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 2,
                QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
                QueueLimit = 4,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 2,
                AutoReplenishment = false
            });
            using var lease = await limiter.AcquireAsync(2);
            Assert.True(lease.IsAcquired);

            var wait1 = limiter.AcquireAsync(1);
            var wait2 = limiter.AcquireAsync(1);
            Assert.False(wait1.IsCompleted);
            Assert.False(wait2.IsCompleted);

            lease.Dispose();
            Assert.True(limiter.TryReplenish());
            Assert.True(limiter.TryReplenish());

            var lease1 = await wait1;
            var lease2 = await wait2;
            Assert.True(lease1.IsAcquired);
            Assert.True(lease2.IsAcquired);
        }
        public override async Task QueueAvailableAfterQueueLimitHitAndResources_BecomeAvailable()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 3,
                QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
                QueueLimit = 2,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 3,
                AutoReplenishment = false
            });
            var lease = limiter.AttemptAcquire(2);
            var wait = limiter.AcquireAsync(2);

            var failedLease = await limiter.AcquireAsync(2);
            Assert.False(failedLease.IsAcquired);

            limiter.TryReplenish();
            limiter.TryReplenish();
            Assert.False(wait.IsCompleted);

            limiter.TryReplenish();
            lease = await wait;
            Assert.True(lease.IsAcquired);

            wait = limiter.AcquireAsync(2);
            Assert.False(wait.IsCompleted);

            limiter.TryReplenish();
            limiter.TryReplenish();
            limiter.TryReplenish();

            lease = await wait;
            Assert.True(lease.IsAcquired);
        }
        public override async Task DropsRequestedLeaseIfPermitCountGreaterThanQueueLimitAndNoAvailability_NewestFirst()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 2,
                QueueProcessingOrder = QueueProcessingOrder.NewestFirst,
                QueueLimit = 1,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 2,
                AutoReplenishment = false
            });
            var lease = limiter.AttemptAcquire(2);
            Assert.True(lease.IsAcquired);

            // Fill queue
            var wait = limiter.AcquireAsync(1);
            Assert.False(wait.IsCompleted);

            var lease1 = await limiter.AcquireAsync(2);
            Assert.False(lease1.IsAcquired);

            limiter.TryReplenish();
            limiter.TryReplenish();

            lease = await wait;
            Assert.True(lease.IsAcquired);
        }
        public override async Task DropsMultipleOldestWhenQueuingMoreThanLimit_NewestFirst()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 2,
                QueueProcessingOrder = QueueProcessingOrder.NewestFirst,
                QueueLimit = 2,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 2,
                AutoReplenishment = false
            });
            var lease = limiter.AttemptAcquire(2);
            Assert.True(lease.IsAcquired);
            var wait = limiter.AcquireAsync(1);
            Assert.False(wait.IsCompleted);

            var wait2 = limiter.AcquireAsync(1);
            Assert.False(wait2.IsCompleted);

            var wait3 = limiter.AcquireAsync(2);
            var lease1 = await wait;
            var lease2 = await wait2;
            Assert.False(lease1.IsAcquired);
            Assert.False(lease2.IsAcquired);
            Assert.False(wait3.IsCompleted);

            limiter.TryReplenish();
            limiter.TryReplenish();

            lease = await wait3;
            Assert.True(lease.IsAcquired);
        }
        public override async Task GetStatisticsWithZeroPermitCount()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 100,
                QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
                QueueLimit = 50,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 3,
                AutoReplenishment = false
            });
            var lease = limiter.AttemptAcquire(0);
            Assert.True(lease.IsAcquired);
            Assert.Equal(1, limiter.GetStatistics().TotalSuccessfulLeases);
            Assert.Equal(100, limiter.GetStatistics().CurrentAvailablePermits);

            lease = await limiter.AcquireAsync(0);
            Assert.True(lease.IsAcquired);
            Assert.Equal(2, limiter.GetStatistics().TotalSuccessfulLeases);
            Assert.Equal(100, limiter.GetStatistics().CurrentAvailablePermits);

            lease = limiter.AttemptAcquire(100);
            Assert.True(lease.IsAcquired);
            Assert.Equal(3, limiter.GetStatistics().TotalSuccessfulLeases);
            Assert.Equal(0, limiter.GetStatistics().CurrentAvailablePermits);

            var lease2 = limiter.AttemptAcquire(0);
            Assert.False(lease2.IsAcquired);
            Assert.Equal(3, limiter.GetStatistics().TotalSuccessfulLeases);
            Assert.Equal(1, limiter.GetStatistics().TotalFailedLeases);
            Assert.Equal(0, limiter.GetStatistics().CurrentAvailablePermits);
        }
        public override async Task DisposeReleasesQueuedAcquires()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 1,
                QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
                QueueLimit = 3,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 1,
                AutoReplenishment = false
            });
            var lease = limiter.AttemptAcquire(1);
            var wait1 = limiter.AcquireAsync(1);
            var wait2 = limiter.AcquireAsync(1);
            var wait3 = limiter.AcquireAsync(1);
            Assert.False(wait1.IsCompleted);
            Assert.False(wait2.IsCompleted);
            Assert.False(wait3.IsCompleted);

            limiter.Dispose();

            lease = await wait1;
            Assert.False(lease.IsAcquired);
            lease = await wait2;
            Assert.False(lease.IsAcquired);
            lease = await wait3;
            Assert.False(lease.IsAcquired);

            // Throws after disposal
            Assert.Throws<ObjectDisposedException>(() => limiter.AttemptAcquire(1));
            await Assert.ThrowsAsync<ObjectDisposedException>(() => limiter.AcquireAsync(1).AsTask());
        }
        public override async Task LargeAcquiresAndQueuesDoNotIntegerOverflow()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(int.MaxValue, QueueProcessingOrder.NewestFirst, int.MaxValue,
                                                                                           TimeSpan.Zero, 2, autoReplenishment: false));
            var lease = limiter.Acquire(int.MaxValue);

            Assert.True(lease.IsAcquired);

            // Fill queue
            var wait = limiter.WaitAndAcquireAsync(3);

            Assert.False(wait.IsCompleted);

            var wait2 = limiter.WaitAndAcquireAsync(int.MaxValue);

            Assert.False(wait2.IsCompleted);

            var lease1 = await wait;

            Assert.False(lease1.IsAcquired);

            limiter.TryReplenish();
            limiter.TryReplenish();
            var lease2 = await wait2;

            Assert.True(lease2.IsAcquired);
        }
        public override async Task CanAcquireResourcesWithAcquireAsyncWithQueuedItemsIfNewestFirst()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 2,
                QueueProcessingOrder = QueueProcessingOrder.NewestFirst,
                QueueLimit = 2,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 3,
                AutoReplenishment = false
            });

            var lease = limiter.AttemptAcquire(1);
            Assert.True(lease.IsAcquired);

            var wait = limiter.AcquireAsync(2);
            Assert.False(wait.IsCompleted);

            Assert.Equal(1, limiter.GetStatistics().CurrentAvailablePermits);
            lease = await limiter.AcquireAsync(1);
            Assert.True(lease.IsAcquired);
            Assert.False(wait.IsCompleted);

            limiter.TryReplenish();
            Assert.True(limiter.TryReplenish());

            Assert.False(wait.IsCompleted);

            Assert.True(limiter.TryReplenish());
            lease = await wait;
            Assert.True(lease.IsAcquired);
        }
        public async Task CanAcquireMultipleRequestsAsync()
        {
            // This test verifies the following behavior
            // 1. when we have available permits after replenish to serve the queued requests
            // 2. when the oldest item from queue is remove to accommodate new requests (QueueProcessingOrder: NewestFirst)
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(4, QueueProcessingOrder.NewestFirst, 4,
                                                                                           TimeSpan.Zero, 3, autoReplenishment: false));

            using var lease = await limiter.WaitAndAcquireAsync(2);

            Assert.True(lease.IsAcquired);
            var wait = limiter.WaitAndAcquireAsync(3);

            Assert.False(wait.IsCompleted);

            Assert.True(limiter.TryReplenish());

            Assert.False(wait.IsCompleted);

            var wait2 = limiter.WaitAndAcquireAsync(2);

            Assert.True(wait2.IsCompleted);

            Assert.True(limiter.TryReplenish());

            var wait3 = limiter.WaitAndAcquireAsync(2);

            Assert.False(wait3.IsCompleted);

            Assert.True(limiter.TryReplenish());
            Assert.True((await wait3).IsAcquired);

            Assert.False((await wait).IsAcquired);
            Assert.Equal(0, limiter.GetAvailablePermits());
        }
        public override async Task CanAcquireResourceAsync()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 2,
                QueueProcessingOrder = QueueProcessingOrder.NewestFirst,
                QueueLimit = 4,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 2,
                AutoReplenishment = false
            });

            using var lease = await limiter.AcquireAsync();

            Assert.True(lease.IsAcquired);
            var wait = limiter.AcquireAsync(2);
            Assert.False(wait.IsCompleted);

            Assert.True(limiter.TryReplenish());

            Assert.False(wait.IsCompleted);

            var wait2 = limiter.AcquireAsync(2);
            Assert.False(wait2.IsCompleted);

            Assert.True(limiter.TryReplenish());

            Assert.True((await wait2).IsAcquired);
        }
        public override async Task CancelUpdatesQueueLimit()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(2, QueueProcessingOrder.NewestFirst, 1,
                                                                                           TimeSpan.Zero, 2, autoReplenishment: false));
            var lease = limiter.Acquire(2);

            Assert.True(lease.IsAcquired);

            var cts  = new CancellationTokenSource();
            var wait = limiter.WaitAndAcquireAsync(1, cts.Token);

            cts.Cancel();
            var ex = await Assert.ThrowsAsync <TaskCanceledException>(() => wait.AsTask());

            Assert.Equal(cts.Token, ex.CancellationToken);

            wait = limiter.WaitAndAcquireAsync(1);
            Assert.False(wait.IsCompleted);

            limiter.TryReplenish();
            limiter.TryReplenish();

            lease = await wait;
            Assert.True(lease.IsAcquired);
            Assert.Equal(1, limiter.GetAvailablePermits());
        }
        public override async Task CannotAcquireResourcesWithAcquireWithQueuedItemsIfOldestFirst()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 2,
                QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
                QueueLimit = 3,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 2,
                AutoReplenishment = false
            });

            var lease = limiter.AttemptAcquire(1);
            Assert.True(lease.IsAcquired);

            var wait = limiter.AcquireAsync(2);
            Assert.False(wait.IsCompleted);

            lease = limiter.AttemptAcquire(1);
            Assert.False(lease.IsAcquired);

            limiter.TryReplenish();
            Assert.True(limiter.TryReplenish());

            lease = await wait;
            Assert.True(lease.IsAcquired);
        }
        public override async Task CanAcquireResourcesWithWaitAndAcquireAsyncWithQueuedItemsIfNewestFirst()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(2, QueueProcessingOrder.NewestFirst, 2,
                                                                                           TimeSpan.Zero, 3, autoReplenishment: false));

            var lease = limiter.Acquire(1);

            Assert.True(lease.IsAcquired);

            var wait = limiter.WaitAndAcquireAsync(2);

            Assert.False(wait.IsCompleted);

            Assert.Equal(1, limiter.GetAvailablePermits());
            lease = await limiter.WaitAndAcquireAsync(1);

            Assert.True(lease.IsAcquired);
            Assert.False(wait.IsCompleted);

            limiter.TryReplenish();
            Assert.True(limiter.TryReplenish());

            Assert.False(wait.IsCompleted);

            Assert.True(limiter.TryReplenish());
            lease = await wait;
            Assert.True(lease.IsAcquired);
        }
        public override async Task QueueAvailableAfterQueueLimitHitAndResources_BecomeAvailable()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(3, QueueProcessingOrder.OldestFirst, 2,
                                                                                           TimeSpan.Zero, 3, autoReplenishment: false));
            var lease = limiter.Acquire(2);
            var wait  = limiter.WaitAndAcquireAsync(2);

            var failedLease = await limiter.WaitAndAcquireAsync(2);

            Assert.False(failedLease.IsAcquired);

            limiter.TryReplenish();
            limiter.TryReplenish();
            Assert.False(wait.IsCompleted);

            limiter.TryReplenish();
            lease = await wait;
            Assert.True(lease.IsAcquired);

            wait = limiter.WaitAndAcquireAsync(2);
            Assert.False(wait.IsCompleted);

            limiter.TryReplenish();
            limiter.TryReplenish();
            limiter.TryReplenish();

            lease = await wait;
            Assert.True(lease.IsAcquired);
        }
        public override async Task GetStatisticsHasCorrectValues()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 100,
                QueueProcessingOrder = QueueProcessingOrder.OldestFirst,
                QueueLimit = 50,
                Window = TimeSpan.Zero,
                SegmentsPerWindow = 2,
                AutoReplenishment = false
            });

            var stats = limiter.GetStatistics();
            Assert.Equal(100, stats.CurrentAvailablePermits);
            Assert.Equal(0, stats.CurrentQueuedCount);
            Assert.Equal(0, stats.TotalFailedLeases);
            Assert.Equal(0, stats.TotalSuccessfulLeases);

            var lease1 = limiter.AttemptAcquire(60);
            stats = limiter.GetStatistics();
            Assert.Equal(40, stats.CurrentAvailablePermits);
            Assert.Equal(0, stats.CurrentQueuedCount);
            Assert.Equal(0, stats.TotalFailedLeases);
            Assert.Equal(1, stats.TotalSuccessfulLeases);

            var lease2Task = limiter.AcquireAsync(50);
            stats = limiter.GetStatistics();
            Assert.Equal(40, stats.CurrentAvailablePermits);
            Assert.Equal(50, stats.CurrentQueuedCount);
            Assert.Equal(0, stats.TotalFailedLeases);
            Assert.Equal(1, stats.TotalSuccessfulLeases);

            limiter.TryReplenish();

            var lease3 = await limiter.AcquireAsync(1);
            Assert.False(lease3.IsAcquired);
            stats = limiter.GetStatistics();
            Assert.Equal(40, stats.CurrentAvailablePermits);
            Assert.Equal(50, stats.CurrentQueuedCount);
            Assert.Equal(1, stats.TotalFailedLeases);
            Assert.Equal(1, stats.TotalSuccessfulLeases);

            var lease4 = limiter.AttemptAcquire(100);
            Assert.False(lease4.IsAcquired);
            stats = limiter.GetStatistics();
            Assert.Equal(40, stats.CurrentAvailablePermits);
            Assert.Equal(50, stats.CurrentQueuedCount);
            Assert.Equal(2, stats.TotalFailedLeases);
            Assert.Equal(1, stats.TotalSuccessfulLeases);

            limiter.TryReplenish();
            await lease2Task;

            stats = limiter.GetStatistics();
            Assert.Equal(50, stats.CurrentAvailablePermits);
            Assert.Equal(0, stats.CurrentQueuedCount);
            Assert.Equal(2, stats.TotalFailedLeases);
            Assert.Equal(2, stats.TotalSuccessfulLeases);
        }
        public override void NullIdleDurationWhenActive()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(1, QueueProcessingOrder.OldestFirst, 2,
                                                                                           TimeSpan.FromMilliseconds(2), 1, autoReplenishment: false));

            limiter.Acquire(1);
            Assert.Null(limiter.IdleDuration);
        }
        public override void AcquireZero_WithAvailability()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(1, QueueProcessingOrder.NewestFirst, 1,
                                                                                           TimeSpan.Zero, 1, autoReplenishment: false));

            using var lease = limiter.Acquire(0);
            Assert.True(lease.IsAcquired);
        }
        public override void NoMetadataOnAcquiredLease()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(1, QueueProcessingOrder.OldestFirst, 1,
                                                                                           TimeSpan.Zero, 2, autoReplenishment: false));

            using var lease = limiter.Acquire(1);
            Assert.False(lease.TryGetMetadata(MetadataName.RetryAfter, out _));
        }
        public override void MetadataNamesContainsAllMetadata()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(1, QueueProcessingOrder.OldestFirst, 1,
                                                                                           TimeSpan.Zero, 1, autoReplenishment: false));

            using var lease = limiter.Acquire(1);
            Assert.Collection(lease.MetadataNames, metadataName => Assert.Equal(metadataName, MetadataName.RetryAfter.Name));
        }
        public void TryReplenishWithAutoReplenish_ReturnsFalse()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(2, QueueProcessingOrder.OldestFirst, 1,
                                                                                           TimeSpan.FromSeconds(1), 1, autoReplenishment: true));

            Assert.Equal(2, limiter.GetAvailablePermits());
            Assert.False(limiter.TryReplenish());
            Assert.Equal(2, limiter.GetAvailablePermits());
        }
        public override void IdleDurationUpdatesWhenChangingFromActive()
        {
            var limiter = new SlidingWindowRateLimiter(new SlidingWindowRateLimiterOptions(1, QueueProcessingOrder.OldestFirst, 2,
                                                                                           TimeSpan.Zero, 2, autoReplenishment: false));

            limiter.Acquire(1);
            limiter.TryReplenish();
            limiter.TryReplenish();
            Assert.NotNull(limiter.IdleDuration);
        }