Test Quality

It activates when you say "add tests" or "improve test coverage" and pushes you toward readable patterns like the AAA structure, descriptive @DisplayName annotations, and AssertJ's fluent chains that actually tell you what failed. The source shows good taste: nested test classes for organization, extracting() for collection verification, and soft assertions when you need multiple checks. It steers you away from assertEquals toward assertThat() with clear failure messages. If you're still writing assertTrue and basic JUnit assertions, this will modernize your test style fast.