--- name: jacoco description: | JaCoCo Java code coverage tool USE WHEN: user mentions "JaCoCo", "Java coverage", "code coverage", asks about "coverage threshold", "jacoco-maven-plugin", "coverage report", "LINE coverage", "BRANCH coverage" DO NOT USE FOR: JavaScript\/TypeScript coverage - use Vitest skill, SonarQube analysis - use `sonarqube` skill, test execution - use testing skills allowed-tools: Read, Grep, Glob --- # JaCoCo - Quick Reference ## Quando Usare Questa Skill - Configurare code coverage in progetti Java\/Maven - Impostare threshold di copertura - Integrare coverage in CI\/CD ## When NOT to Use This Skill - **JavaScript\/TypeScript coverage** - Use Vitest skill for frontend coverage - **SonarQube configuration** - Use `sonarqube` skill for quality gates - **Test writing** - Use Spring Boot Test or JUnit skills - **Gradle projects** - JaCoCo works but syntax differs from Maven > **Deep Knowledge**: Use `mcp__documentation__fetch_docs` with technology: `jacoco` for comprehensive documentation. ## Pattern Essenziali ### Maven Configuration ```xml org.jacoco<\/groupId> jacoco-maven-plugin<\/artifactId> 0.8.12<\/version> prepare-agent<\/id> prepare-agent<\/goal><\/goals> <\/execution> report<\/id> test<\/phase> report<\/goal><\/goals> <\/execution> check<\/id> check<\/goal><\/goals> BUNDLE<\/element> LINE<\/counter> COVEREDRATIO<\/value> 0.80<\/minimum> <\/limit> <\/limits> <\/rule> <\/rules> <\/configuration> <\/execution> <\/executions> <\/plugin> ``` ### Exclusions ```xml com.company.config.*<\/exclude> com.company.dto.*<\/exclude> com.company.entity.*<\/exclude> com.company.mapper.*Impl<\/exclude> <\/excludes> ``` ### Comandi ```bash mvn clean verify # Test + coverage check mvn jacoco:report # Genera report open target\/site\/jacoco\/index.html # Visualizza ``` ## Counter Types | Counter | Descrizione | |---------|-------------| | `LINE` | Righe di codice | | `BRANCH` | Branch if\/switch | | `METHOD` | Metodi | ## Anti-Patterns | Anti-Pattern | Why It's Bad | Correct Approach | |--------------|--------------|------------------| | Aiming for 100% coverage | Diminishing returns, test bloat | Target 80% LINE, 70% BRANCH | | Including DTOs\/entities in coverage | Inflates numbers, no logic to test | Exclude with `` | | Only checking LINE coverage | Misses untested branches | Check both LINE and BRANCH | | No coverage threshold in CI | Can't enforce quality | Add `` goal with minimums | | Excluding too much code | False sense of security | Only exclude generated\/config code | | Not versioning jacoco.exec | Can't track coverage trends | Archive reports in CI | ## Quick Troubleshooting | Issue | Likely Cause | Solution | |-------|--------------|----------| | Coverage report shows 0% | Tests not running with agent | Ensure `prepare-agent` goal runs before tests | | Build fails on coverage check | Coverage below threshold | Add tests or adjust minimum in `` | | Report excludes nothing | Wrong exclude pattern | Use fully qualified names (com.company.dto.*) | | Report missing classes | Classes not loaded during tests | Add integration tests to cover them | | Coverage lower in CI than local | Different test execution | Ensure CI runs all test phases | | SonarQube shows no coverage | Wrong report path | Check `sonar.coverage.jacoco.xmlReportPaths` | ## Approfondimenti > Per configurazioni avanzate: `mcp__documentation__fetch_docs` > - Technology: `jacoco` (not yet in MCP - use official docs) > - [JaCoCo Docs](https:\/\/www.jacoco.org\/jacoco\/trunk\/doc\/)