/test-coverage

Test Coverage Command

Analyze and report test coverage

Instructions

Follow this systematic approach to analyze and improve test coverage: **$ARGUMENTS**

1. **Coverage Tool Setup**

• Identify and configure appropriate coverage tools:
• JavaScript/Node.js: Jest, NYC, Istanbul
• Python: Coverage.py, pytest-cov
• Java: JaCoCo, Cobertura
• C#: dotCover, OpenCover
• Ruby: SimpleCov
• Configure coverage reporting formats (HTML, XML, JSON)
• Set up coverage thresholds and quality gates

2. **Baseline Coverage Analysis**

• Run existing tests with coverage reporting
• Generate comprehensive coverage reports
• Document current coverage percentages:
• Line coverage
• Branch coverage
• Function coverage
• Statement coverage
• Identify uncovered code areas

3. **Coverage Report Analysis**

• Review detailed coverage reports by file and directory
• Identify critical uncovered code paths
• Analyze branch coverage for conditional logic
• Find untested functions and methods
• Examine coverage trends over time

4. **Critical Path Identification**

• Identify business-critical code that lacks coverage
• Prioritize high-risk, low-coverage areas
• Focus on public APIs and interfaces
• Target error handling and edge cases
• Examine security-sensitive code paths

5. **Test Gap Analysis**

• Categorize uncovered code:
• Business logic requiring immediate testing
• Error handling and exception paths
• Configuration and setup code
• Utility functions and helpers
• Dead or obsolete code to remove

6. **Strategic Test Writing**

• Write unit tests for uncovered business logic
• Add integration tests for uncovered workflows
• Create tests for error conditions and edge cases
• Test configuration and environment-specific code
• Add regression tests for bug-prone areas

7. **Branch Coverage Improvement**

• Identify uncovered conditional branches
• Test both true and false conditions
• Cover all switch/case statements
• Test exception handling paths
• Verify loop conditions and iterations

8. **Edge Case Testing**

• Test boundary conditions and limits
• Test null, empty, and invalid inputs
• Test timeout and network failure scenarios
• Test resource exhaustion conditions
• Test concurrent access and race conditions

9. **Mock and Stub Strategy**

• Mock external dependencies for better isolation
• Stub complex operations to focus on logic
• Use dependency injection for testability
• Create test doubles for external services
• Implement proper cleanup for test resources

10. **Performance Impact Assessment**

• Measure test execution time with new tests
• Optimize slow tests without losing coverage
• Parallelize test execution where possible
• Balance coverage goals with execution speed
• Consider test categorization (fast/slow, unit/integration)

11. **Coverage Quality Assessment**

• Ensure tests actually verify behavior, not just execution
• Check for meaningful assertions in tests
• Avoid testing implementation details
• Focus on testing contracts and interfaces
• Review test quality alongside coverage metrics

12. **Framework-Specific Coverage Enhancement**

**For Web Applications:**

• Test API endpoints and HTTP status codes
• Test form validation and user input handling
• Test authentication and authorization flows
• Test error pages and user feedback

**For Mobile Applications:**

• Test device-specific functionality
• Test different screen sizes and orientations
• Test offline and network connectivity scenarios
• Test platform-specific features

**For Backend Services:**

• Test database operations and transactions
• Test message queue processing
• Test caching and performance optimizations
• Test service integrations and API calls

13. **Continuous Coverage Monitoring**

• Set up automated coverage reporting in CI/CD
• Configure coverage thresholds to prevent regression
• Generate coverage badges and reports
• Monitor coverage trends and improvements
• Alert on significant coverage decreases

14. **Coverage Exclusion Management**

• Properly exclude auto-generated code
• Exclude third-party libraries and dependencies
• Document reasons for coverage exclusions
• Regularly review and update exclusion rules
• Avoid excluding code that should be tested

15. **Team Coverage Goals**

• Set realistic coverage targets based on project needs
• Establish minimum coverage requirements for new code
• Create coverage improvement roadmap
• Review coverage in code reviews
• Celebrate coverage milestones and improvements

16. **Coverage Reporting and Communication**

• Generate clear, actionable coverage reports
• Create coverage dashboards for stakeholders
• Document coverage improvement strategies
• Share coverage results with development team
• Integrate coverage into project health metrics

17. **Mutation Testing (Advanced)**

• Implement mutation testing to validate test quality
• Identify tests that don't catch actual bugs
• Improve test assertions and edge case coverage
• Use mutation testing tools specific to your language
• Balance mutation testing cost with quality benefits

18. **Legacy Code Coverage Strategy**

• Prioritize high-risk legacy code for testing
• Use characterization tests for complex legacy systems
• Refactor for testability where possible
• Add tests before making changes to legacy code
• Document known limitations and technical debt

**Sample Coverage Commands:**

# JavaScript with Jest
npm test -- --coverage --coverage-reporters=html,text,lcov

# Python with pytest
pytest --cov=src --cov-report=html --cov-report=term

# Java with Maven
mvn clean test jacoco:report

# .NET Core
dotnet test --collec