public async Task Test_StatsAreCorrectlyUpdated_AfterDequeue_NoTaskType()
        {
            PostgreSqlTaskQueueInfo taskQueueInfo =
                CreateTaskQueueInfo(() => mDataSource.LastPostedAt);

            using (PostgreSqlTaskQueueConsumer taskQueueConsumer =
                       CreateTaskQueueConsumer(() => mDataSource.LastPostedAt))
                using (TaskQueueMetricsDiffChecker diff = new TaskQueueMetricsDiffChecker(async()
                                                                                          => await taskQueueInfo.ComputeMetricsAsync()))
                {
                    await diff.CaptureInitialMetricsAsync();

                    IQueuedTaskToken dequeuedToken = await taskQueueConsumer
                                                     .DequeueAsync();

                    QueuedTaskStatus origStatus = mDataSource
                                                  .GetOriginalTokenData(dequeuedToken.DequeuedTask.Id)
                                                  .LastQueuedTaskResult
                                                  .Status;

                    await diff.CaptureNewMetricsAndAssertCorrectDiff(delta : new TaskQueueMetrics(
                                                                         totalUnprocessed: origStatus == QueuedTaskStatus.Unprocessed ? -1 : 0,
                                                                         totalProcessing: 1,
                                                                         totalErrored: origStatus == QueuedTaskStatus.Error ? -1 : 0,
                                                                         totalFaulted: origStatus == QueuedTaskStatus.Faulted ? -1 : 0,
                                                                         totalFataled: origStatus == QueuedTaskStatus.Fatal ? -1 : 0,
                                                                         totalProcessed: origStatus == QueuedTaskStatus.Processed ? -1 : 0));
                }
        }
        public async Task Test_StatsAreUpdatedCorrectly_AfterEnqueue_RepostExistingTask()
        {
            Faker faker =
                new Faker();

            DateTimeOffset postedAt = mDataSource.LastPostedAt
                                      .AddTicks(1);

            PostgreSqlTaskQueueProducer taskQueueProducer =
                CreateTaskQueueProducer(() => postedAt);

            PostgreSqlTaskQueueInfo taskQueueInfo =
                CreateTaskQueueInfo(() => postedAt);

            foreach (IQueuedTaskToken token in mDataSource.CanBeRepostedSeededTaskTokens)
            {
                using (TaskQueueMetricsDiffChecker diff = new TaskQueueMetricsDiffChecker(async()
                                                                                          => await taskQueueInfo.ComputeMetricsAsync()))
                {
                    QueuedTaskStatus prevStatus = token
                                                  .LastQueuedTaskResult
                                                  .Status;

                    await diff.CaptureInitialMetricsAsync();

                    QueuedTaskInfo repostTaskInfo = new QueuedTaskInfo()
                    {
                        Id            = token.DequeuedTask.Id,
                        Priority      = faker.Random.Int(1, 100),
                        Payload       = token.DequeuedTask.Payload,
                        Source        = nameof(Test_StatsAreUpdatedCorrectly_AfterEnqueue_RepostExistingTask),
                        Type          = token.DequeuedTask.Type,
                        LockedUntilTs = postedAt.AddMinutes(faker.Random.Long(1000, 10000))
                    };

                    //Remove task record from DB - only dequeued tasks get reposted
                    await mDataSource.RemoveQueuedTaskFromDbByIdAsync(token
                                                                      .DequeuedTask
                                                                      .Id);

                    await taskQueueProducer.EnqueueAsync(repostTaskInfo);

                    await diff.CaptureNewMetricsAndAssertCorrectDiff(delta : new TaskQueueMetrics(
                                                                         totalUnprocessed: prevStatus != QueuedTaskStatus.Unprocessed ? 1 : 0,
                                                                         totalProcessing: prevStatus == QueuedTaskStatus.Processing ? -1 : 0,
                                                                         totalErrored: prevStatus == QueuedTaskStatus.Error ? -1 : 0,
                                                                         totalFaulted: prevStatus == QueuedTaskStatus.Faulted ? -1 : 0,
                                                                         totalFataled: prevStatus == QueuedTaskStatus.Fatal ? -1 : 0,
                                                                         totalProcessed: prevStatus == QueuedTaskStatus.Processed ? -1 : 0));
                }
            }
        }
        public async Task Test_StatsAreUpdatedCorrectly_AfterEnqueue_NewTask()
        {
            Faker faker =
                new Faker();

            DateTimeOffset postedAt = mDataSource.LastPostedAt
                                      .AddTicks(1);

            PostgreSqlTaskQueueProducer taskQueueProducer =
                CreateTaskQueueProducer(() => postedAt);

            PostgreSqlTaskQueueInfo taskQueueInfo =
                CreateTaskQueueInfo(() => postedAt);

            using (PostgreSqlTaskQueueConsumer taskQueueConsumer =
                       CreateTaskQueueConsumer(() => postedAt))
                using (TaskQueueMetricsDiffChecker diff = new TaskQueueMetricsDiffChecker(async()
                                                                                          => await taskQueueInfo.ComputeMetricsAsync()))
                {
                    await taskQueueConsumer.StartReceivingNewTaskUpdatesAsync();

                    Assert.IsTrue(taskQueueConsumer.IsReceivingNewTaskUpdates);

                    //Capture previous metrics
                    await diff.CaptureInitialMetricsAsync();

                    await taskQueueProducer.EnqueueAsync(payload : new SampleTaskPayload(100),
                                                         source : nameof(Test_StatsAreUpdatedCorrectly_AfterEnqueue_NewTask),
                                                         priority : faker.Random.Int(1, 100));

                    //Check that new metrics differ from the previous ones as expected
                    await diff.CaptureNewMetricsAndAssertCorrectDiff(delta : new TaskQueueMetrics(
                                                                         totalUnprocessed: 1,
                                                                         totalProcessing: 0,
                                                                         totalErrored: 0,
                                                                         totalFaulted: 0,
                                                                         totalFataled: 0,
                                                                         totalProcessed: 0));
                }
        }