java-testing

JUnit 5 integration tests with Testcontainers spin up real dependencies like PostgreSQL to validate Java persistence behavior. You configure Testcontainers to launch database instances during tests, ensuring repository interactions match production environments accurately.

MockMvc tests Spring HTTP API behavior by simulating requests against controllers without starting a full server. You verify endpoint mappings, response statuses, and JSON payloads while mocking service dependencies to isolate controller logic validation.

PIT mutation testing modifies Java bytecode during tests to check if existing tests detect injected faults. Configuring PIT thresholds enforces test suite quality by failing the build when mutations survive, indicating inadequate test coverage.

ArchUnit prevents architectural drift by enforcing boundary rules across Java packages in automated tests. You define constraints like layer dependencies and naming conventions, then run them continuously to catch structural violations early.

Yes, JUnit 5 with AssertJ and Mockito is required for the test suite design. JUnit 5 provides the testing framework, AssertJ offers fluent assertions for readable tests, and Mockito handles mocking dependencies for isolated unit testing.

Readable JUnit 5 unit tests use Given-When-Then structures, parametrized tests for multiple inputs, and nested test classes for grouping related scenarios. This approach improves maintainability and clearly expresses business logic validation intent.