One possible definition for legacy code is "Code without tests", and as you may know, changing code that doesn't have tests can be challenging and scary, and it's often advised to introduce tests before making any change.
Unfortunately, adding tests to an existing codebase is a challenge as well.
In this talk, I demonstrate how using Approval Testing and safe refactorings help to reintroduce tests in a codebase where dependency inversion is not a thing, where we use random, time, UUIDs, and indirect outputs.
This talk is done in the form of a live-coding and, to this day, still needs to be recorded.