Not long ago in Akka.NET-land we had an issue occur where users noticed a dramatic drop in throughput in Akka.Remote’s message processing pipeline - and to make matters worse, this occurred in a production release of AKka.NET!

Yikes, how did that happen?

The answer is that although you can use unit tests and code reviews to detect functional problems with code changes and pull requests, using those same mechanisms to detect performance problems with code is utterly ineffective. Even skilled developers who have detailed knowledge about the internals of the .NET framework and CLR are unable to correctly predict how changes to code will impact its performance.

Hence why I developed NBench - a .NET performance-testing, stress-testing, and benchmarking framework for .NET applications that works and feels a lot like a unit test.

How to Unit Test Akka.NET Actors with Akka.TestKit

An Introduction to the Akka.TestKit

In this post we introduce the Akka.TestKit module - a library that makes it easy to unit test Akka.NET actors using all of the popular .NET unit testing frameworks.

A Brief End-to-End Akka.TestKit Example

Before going deep into the TestKit, here’s an end-to-end example of what a test usually looks like.

[TestFixture] //using NUnit
public class UserIdentityActorSpecs : TestKit{

    public void UserIdentityActor_should_confirm_user_creation_success()
        var identity = Sys.ActorOf(Props.Create(() => new UserIdentityActor()));
        identity.Tell(new UserIdentityActor.CreateUserWithValidUserInfo());
        var result = ExpectMsg<UserIdentityActor.OperationResult>().Successful;


80% of your tests will be this simple: create an actor, send it a message, and expect a response back. Let’s explore how to do it.

The concepts in this post were first introduced in a talk at the 2015 Cassandra Summit.

I’ve been a .NET developer for roughly 10 years now - since the summer after my freshman year in college in 2005 I’ve been developing in Visual Studio and .NET. I’ve founded three startups on .NET, worked for Microsoft, and founded multiple successful OSS projects in .NET - I say all of this in evidence to the depth of my commitment and investment in the .NET ecosystem.

But it’s time we, the .NET community, address a major elephant in the room - .NET is, and often has been, way behind in other ecosystems in terms of overall innovation, openness to new ideas, and flexibility.

The Experience of Being a .NET Developer

.NET has been, historically, an expensive ecosystem to play in.

Because to play in it, you have to do so by Microsoft’s rules.

It's Ballmer's World, Bro

  • You have to buy a license for Visual Studio, or more likely, an MSDN subscription.
  • You have to buy a license for Windows Server.
  • You have to buy a license for Windows Server.
  • You have to develop your web applications in a framework built by Microsoft, like ASP.NET or WCF.
  • You have to host your web applications in IIS.

And the list goes on - the point being that our entire way of developing our own products depends on a single company in Redmond choosing what tools it wants to make available to us at any given time and price.

The Impact of Marrying .NET to Microsoft

I want to share with you a little story from a point in my career with Microsoft during 2010-2011. By 2011 HTML5 had become mostly standardized and its...