I Tested an OpenRewrite Recipe: The Mistakes I Made and How to Fix Them

In this post, I migrated my ad hoc test code to rely on OpenRewrite's provided classes. Even though they are not exempt from criticism, they offer a solid abstraction layer and make tests more maintainable.

For the last two weeks, I've kicked the tires of OpenRewrite. At first, I created a recipe to move Kotlin source files as per the official recommendations with a set package name. I then improved the recipe to compute the root automatically. In both versions, I thoroughly tested the recipe. However, my testing approach was wrong. In this post, I want to describe my mistakes, and how I fixed them.

The Naive Approach

I originally approached the testing of the recipe in a very naive way, to say the least. As explained in the first post, I used OpenRewrite's low-level APIs. Here's what I wrote:

// Given ...