A complete guide to testing Spring Boot applications with JUnit 6. Covers unit tests with plain JUnit, slice tests (@WebMvcTest, @DataJpaTest, @JsonTest), full integration tests with @SpringBootTest, context caching, Testcontainers, and best practices for each layer.
Advanced JUnit 6 extension patterns: composed meta-annotations, automatic retry extensions, soft assertions via ParameterResolver, and custom invocation strategies with @TestTemplate. Complete runnable examples showing how to build a domain-specific testing framework.
A step-by-step guide to building a complete, runnable custom JUnit 6 TestEngine from scratch. Covers TestDescriptor trees, the discovery and execution phases, ServiceLoader registration, and a full CSV-based test engine example with real output.
An in-depth look at JUnit 6 internals: the two-phase discovery and execution model, the TestDescriptor tree, the EngineExecutionListener event chain, UniqueId addressing, and programmatic test plan inspection with complete runnable code examples.
A complete guide to JUnit 6 parallel test execution: enabling and configuring parallelism, class vs method level concurrency, @Execution and @ResourceLock annotations, thread pool strategies, pitfall table with fixes, and real performance benchmarks.
A step-by-step guide to building JUnit 6 extensions. Covers all extension interfaces: lifecycle callbacks, ParameterResolver, TestExecutionExceptionHandler, @RegisterExtension with configuration, the ExtensionContext.Store, and a complete interface reference table.
A complete guide to using @Tag in JUnit 6 to categorize tests, build test suites, filter by tag at build time using Maven and Gradle, and apply tagging strategies for fast vs slow, unit vs integration, and feature-flag-based test selection.
A complete guide to JUnit 6 dynamic tests using @TestFactory. Covers DynamicTest, DynamicContainer, real-world use cases (live data sources, file-based tests), supported return types, and key differences from @ParameterizedTest.
A complete guide to JUnit 6 parameterized tests: every argument source explained with code examples. Covers @ValueSource, @CsvSource, @CsvFileSource, @MethodSource, @EnumSource, @NullSource, @EmptySource, and custom @ArgumentsSource providers.
Learn how to use @Nested in JUnit 6 to organise tests into scenario-based inner class groups. Covers lifecycle composition, real-world patterns for REST controllers and domain services, nesting rules, and a complete ShoppingCart example with full test report output.