521 Frameworks Micronaut Testing Unit Tests

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

• Read reference and assess project context

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