Micronaut Unit Testing

Apply fast testing strategies for Micronaut: Mockito-first, narrow @MicronautTest when HTTP or DI replacement is required.

What is covered in this Skill?

• Pure JUnit 5 + Mockito without container boot
• @MicronautTest with @MockBean factory methods for collaborators
• HttpClient blocking exchanges against the embedded server
• @Property for deterministic configuration in tests
• @ParameterizedTest with @CsvSource / @MethodSource
• Naming: *Test → Surefire; *IT → Failsafe when configured
• When to escalate to @522

Scope: Apply recommendations based on the reference rules and good/bad code examples.

Constraints

Compile before test refactors; verify the full suite after.

• 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 examples
• 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

• Add or improve unit tests in a Micronaut project
• Reduce unnecessary @MicronautTest usage with Mockito-first tests
• Write Mockito-first unit tests for Micronaut services
• Mock Micronaut bean collaborators in unit tests
• Review fast Micronaut tests without application context

Workflow

1. Read reference and assess project context

Read references/521-frameworks-micronaut-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/521-frameworks-micronaut-testing-unit-tests.md.