/ Guides

Guides

Practical notes on mutation testing with StrykerJS: how to run it on the pull request diff, why it is slow on small diffs, what incremental mode does to the score, and how to check tests that an agent wrote. The numbers come from Reapr's own measurements, with sources. Each guide is also available as Markdown for agents, and all of them are in one text file.

  1. How to speed up a slow Stryker run

    Where a small StrykerJS run spends its time, and the ignorePatterns, checker, logLevel and concurrency settings that change it.

  2. Mutation testing on pull requests

    Why mutation testing belongs on the pull request diff, and how to scope a StrykerJS run to it, with or without Reapr.

  3. Why Stryker's incremental score covers the whole package

    Why StrykerJS with incremental true and --mutate ranges reports a package-wide score, and how Reapr gets the score of the diff.

  4. Mutation testing for AI-generated code

    Why coverage cannot check tests that an agent wrote, how surviving mutants can, and the rules Reapr's mutation-audit agent skill follows.