Tests that had never failed, written by an AI and passed by everyone: mutation testing with Stryker.NET

A shopkeeper looks down at two paper bags he holds on his counter, labelled page 1 and page 2 and each holding the same coffee pot and mug, beside a clipboard already ticked, under a blackboard that asks would anybody notice.

What mutation testing finds that code coverage cannot, how to read a Stryker.NET report, and when to run it on a .NET project.