321-frameworks-spring-boot-testing-unit-tests
About 321-frameworks-spring-boot-testing-unit-tests
A skill for applying Mockito-oriented unit testing practices in Spring Boot projects. It emphasizes tests without a Spring context where suitable, controller and JSON slice tests, parameterized tests, and deterministic test setup.
Key features
- 01Mockito-based service unit tests
- 02Controller tests with @WebMvcTest
- 03JSON assertions with @JsonTest
- 04Parameterized test patterns
- 05Deterministic clock configuration
- 06Current Mockito bean annotations
Use cases
- 01Test Spring services without loading context
- 02Test controller request and response behavior
- 03Verify JSON serialization values
- 04Replace duplicated cases with parameterized tests
Install
Copy the command and run it in a terminal.
npx skills add https:/ / github.com/ jabrena/ plinth --skill 321-frameworks-spring-boot-testing-unit-testsAfter installing, type/321-frameworks-spring-boot-testing-unit-testsin Claude Code to confirm it loaded.
Bundled filesreferences/321-frameworks-spring-boot-testing-unit-tests.md
Details
From the project READMESpring 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 compileormvn compilebefore applying any change - SAFETY: If compilation fails, stop immediately
- VERIFY: Run
./mvnw clean verifyormvn clean verifyafter 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
- Write Mockito-first unit tests for Spring Boot services
- Avoid unnecessary @SpringBootTest in Spring unit tests
- Review Spring Boot slice-free unit test design
Workflow
- 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.
- Gather scope and decide target improvements
Identify requested outcomes, constraints, and the minimum safe set of changes to apply.
- Apply framework-aligned changes
Implement or refactor configuration/code following the reference patterns and project conventions.
- 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.