public void AddMessage_WhenMessageAdded_ExpectOnBuffer() { // Arrange var mockQueueWrapper = new Mock <IQueueWrapper>(); var mockQueueMessageSerializer = new Mock <IQueueMessageSerializer>(); mockQueueMessageSerializer.Setup(r => r.GetVersionedMessage(It.IsAny <string>())) .Returns(new VersionedMessage()); var buffer = new Buffer(this.LoggerFactory, mockQueueWrapper.Object, mockQueueMessageSerializer.Object); // Act var stopwatch = Stopwatch.StartNew(); buffer.AddMessage("data"); stopwatch.Stop(); // Assert this.WriteTimeElapsed(stopwatch); var versionedMessages = buffer.InternalBuffer.ToList(); Assert.That(versionedMessages.Count, Is.EqualTo(1)); }