Stryker.NET VS Mecha

Bogus - For creating fake data Verify - Snapshot testing for .NET MELT - For testing ILogger usage Stryker - Mutation Testing for .NET TestContainers - run docker programmatically in integration tests

This is called mutation testing btw.

Let's try it on our small example using Stryker.

There are tools that do this automatically, stryker[2] is one of them. When you run stryker, it will create many mutant versions of your production code, and run your tests for each mutant (that's how mutations are called in stryker's' documentation) version of the code. If your tests fail then the mutant is killed. If your tests passed, the mutant survived. Let's have a look at the the result of runnning stryker against reffects-store's code:

Mutation testing is pretty solid. Better than code coverage for sure. Using Stryker personally.

A mutation testing tool (like Stryker) runs your unit tests to verify they all pass then makes a small change (mutation) to your code and reruns the tests. At least one test should fail because the modified code should behave differently.

I haven't tried it yet, but last time I researched it, this is the library that looked most promising: https://stryker-mutator.io/

Website: https://stryker-mutator.io/

Because of the above I've generally been using tools like Stryker.NET and FsCheck to augment my testing suite. I'm still doing unit testing to find the more obvious "I haven't had my coffee, let's make sure I'm doing what I think I'm doing" bugs. I'm just using things like mutation testing, property testing, fuzzing, etc. to find the deeper issues in my code. There's a ton of libraries out there, including one that I've built for myself to help with testing but FsCheck and Stryker are just beautiful. And if you're interested in fuzzing, SharpFuzz is a great option. But that one isn't quite as easy of an on ramp compared to the other two that I mentioned.