Tired of brittle test setups and copy-pasted builders? Learn how to manage unit test data with maintainable, flexible factories. This guide walks through test factory patterns in Java (and other languages), helping you avoid flaky tests, reduce duplication, and write more resilient test suites.

One of the first things we teach aspiring software engineers is the principle Don't Repeat Yourself. While this is a very useful rule of thumb, it doesn't apply in every case. In this post we will discuss when it does not.