Mighty Moose a/k/a ContinuousTests

Introduction

At my current place of employment, I was introduced to NCrunch, a continuous testing solution for .NET and Visual Studio. It’s a great tool that I really enjoy using at work. However, for at home use, I can’t justify paying their asking price for a personal license. Don’t get me wrong, I really love the tool, and if I were doing some serious development on my own (i.e. creating products for sale as a side job), I’d probably pay for it, because it’s fast and shows exactly where an exception occurred or a test failed.

So I really like this concept of continuous testing and went on an Internet search to see what was available out there for free. I wanted something that would run in Visual Studio 2012/2013. A lot of the “free” tools use external test runners which display their output in either the browser (as an XML/HTML page) or in a console window. I don’t like those tools because they interrupt my context, having to switch between Visual Studio and, say, a console window. Plus, then I have to go digging for the file and line number when a test fails.

Enter Mighty Moose a/k/a Continuous Tests

During my search, I found Mighty Moose a/k/a ContinuousTests, by Greg Young. Mighty Moose has a slightly different philosophy about continuous testing. Instead of a code coverage margin in Visual Studio, they have a risk margin. The risk margin shows a colored circle next to a method under test with a number inside. The number inside tells you how many tests are covering the method. The color: red, green, or yellow, indicates the risk of changing that method.

How is risk calculated? It’s based on how close the method was called from the test. According to Greg, while code coverage tells you whether or not the code was executed by a test, that information alone is not enough to classify how risky it is to change the code. What if the code that’s “covered” was called from a method 10 frames down the call stack? By changing that code, you could be affecting not just the method under test, but all 8 other methods in the call stack.

In addition to the risk margin, Mighty Moose contains graph “overlay” graphics (for those of us who can’t afford Visual Studio Ultimate ;) ) that show the call graph of all methods called during the test. This can help you gauge “how far away” a method was invoked from the test, and in general, just help you see the entire call graph, which in itself, could be enlightening.

Getting Mighty Moose to Work with Visual Studio 2013

Mighty Moose is currently at version 1.0.47. It officially only supports Visual Studio 2008, 2010, and 2012. However, there’s an excellent question over on Stack Overflow that I contributed to which shows you how to get Mighty Moose to work with Visual Studio 2013.