321-frameworks-spring-boot-testing-unit-tests

# Spring Boot Unit Testing with Mockito Apply Spring Boot unit testing guidelines with Mockito. **What is covered in this Skill?** - Pure unit tests: @ExtendWith(MockitoExtension.class), @Mock, @InjectMocks for @Service/@Component (no Spring context) - Slice tests: @WebMvcTest, @MockitoBean for controllers (Spring Boot 4.0.x — @MockBean removed) - @JsonTest for JSON serialization with correct JSON value assertions (extractingJsonPathStringValue, etc.) - Parameterized tests: @ParameterizedTest with @CsvSource or @MethodSource over copy-pasted methods - Java records for domain objects in tests - @TestConfiguration, @ActiveProfiles, @Primary fixed-clock beans for deterministic test setup - Modern mocking API: @MockitoBean / @MockitoSpyBean; @MockBean/@SpyBean are deprecated/removed in Boot 4.0.x **Scope:** Apply recommendations based on the reference rules and good/bad code examples. For integration tests use @322-frameworks-spring-boot-testing-integration-tests. ## Constraints Before applying any test changes, ensure the project compiles. If compilation fails, stop immediately. After applying improvements, run full verification. - **MANDATORY**: Run `./mvnw compile` or `mvn compile` before applying any change - **SAFETY**: If compilation fails, stop immediately - **VERIFY**: Run `./mvnw clean verify` or `mvn clean verify` after applying improvements - **BEFORE APPLYING**: Read the reference for detailed rules and good/bad patterns - **EDGE CASE**: If request scope is ambiguous, stop and ask a clarifying question before applying changes - **EDGE CASE**: If required inputs, files, or tooling are missing, report what is missing and ask whether to proceed with setup guidance ## When to use this skill - Review Java code for Spring Boot unit tests - Apply best practices for Spring Boot unit tests in Java code ## Workflow 1. **Read reference and assess project context** Read `references/321-frameworks-spring-boot-testing-unit-tests.md` and inspect the current project setup before proposing changes. 2. **Gather scope and decide target improvements** Identify requested outcomes, constraints, and the minimum safe set of changes to apply. 3. **Apply framework-aligned changes** Implement or refactor configuration/code following the reference patterns and project conventions. 4. **Run verification and report results** Execute appropriate build/tests and summarize what changed, what was verified, and any follow-up actions. ## Reference For detailed guidance, examples, and constraints, see [references/321-frameworks-spring-boot-testing-unit-tests.md](references/321-frameworks-spring-boot-testing-unit-tests.md).