public async Task MockPollQueueAsync_ShouldRetrieveMessageWithAsyncProcessor_WhenQueueAndMessageExists() { var client = new SQSClientMock("mockEndpoint", "mockRegion"); await client.CreateStandardFifoQueueAsync("mockQueue.fifo"); await client.SendMessageAsync("Hello World!", "mockQueue.fifo"); var cancellationToken = client.PollQueueAsync("mockQueue.fifo", 1, 1, async(message) => { Assert.Equal("Hello World!", message); _messagePicked = true; return(await Task.FromResult(true)); }); Task.Delay(1000).Wait(); cancellationToken.Cancel(); Assert.True(_messagePicked); _messagePicked = false; }