A complete guide to mutation testing with PIT (Pitest) and JUnit 6. Covers what mutation testing is, Maven and Gradle setup, reading mutation reports, surviving mutant analysis, and how to use PIT to measure true test suite quality beyond code coverage.
A complete guide to property-based testing in JUnit 6 with jqwik. Covers @Property, @ForAll, constraint annotations, custom Arbitraries, domain-specific generators, shrinking, seed-based reproduction, and when property testing complements example-based tests.
A catalogue of the most common JUnit testing mistakes with before/after code fixes. Covers testing implementation details, missing assertion messages, swapped assertEquals arguments, @SpringBootTest misuse, tests without assertions, and unseeded random data.
A performance optimization guide for slow JUnit 6 test suites. Covers measuring bottlenecks, Spring context duplication, using wrong test type, Testcontainers restarts, sequential execution, and provides a summary table with typical time savings per optimization.
A complete guide to identifying and permanently fixing flaky JUnit 6 tests. Covers all major root causes: shared mutable state, time dependency, Thread.sleep, port conflicts, file system races, order-dependent database tests, and async timing issues — each with proven fixes.
A systematic guide to debugging JUnit 6 test failures. Covers reading error messages like a pro, running tests in isolation, diagnostic assertions, IntelliJ IDEA debug techniques, common failure patterns (NPE, shared state, wrong argument order, unnecessary stubs), and a debugging toolkit table.
A systematic playbook for migrating JUnit 4 tests to JUnit 6. Covers annotation mapping, complete before/after code for @Rule, @RunWith, parameterized tests, Mockito integration, and a phase-by-phase migration strategy using the Vintage engine for zero-downtime upgrades.
A practical guide to applying Clean Code principles to JUnit 6 test code. Covers the FIRST principles, DRY vs DAMP, meaningful test structure, avoiding test smells, and real before/after refactoring examples that transform brittle tests into living documentation.
An honest comparison of the Test Pyramid and Test Trophy testing models, with JUnit 6 code examples for each approach, analysis of when each model works best, and a practical hybrid strategy for real-world Java projects.
A practical guide comparing unit, integration, and E2E tests in JUnit 6. Covers precise definitions, full code examples for each layer, speed and reliability trade-offs, recommended proportions, and guidance on when to write each type.