Test Coverage Analysis
Test coverage analysis helps you understand how much of your code is tested by your test suite. This tool analyzes coverage reports and provides insights to improve your testing strategy.
Types of Coverage Metrics
1. Line Coverage
Measures the percentage of executable lines of code that are executed by tests.
- Shows which lines are executed during testing
- Helps identify untested code paths
- Most common and basic coverage metric
2. Branch Coverage
Measures the percentage of branches (decision points) that are tested.
- Ensures both true and false conditions are tested
- More comprehensive than line coverage
- Identifies untested conditional logic
3. Function Coverage
Measures the percentage of functions that are called by tests.
- Shows which functions are never executed
- Helps identify dead code
- Useful for API and library testing
4. Statement Coverage
Similar to line coverage but focuses on individual statements.
- Accounts for multiple statements per line
- More granular than line coverage
- Language-dependent metric
Coverage Analysis Benefits
- Quality Assurance: Higher coverage often indicates better testing
- Risk Assessment: Identify high-risk untested areas
- Regression Prevention: Ensure new code is properly tested
- Refactoring Confidence: Safe code changes with good coverage
- Team Accountability: Objective testing metrics
Best Practices
- Aim for 80%+ line coverage, 70%+ branch coverage
- Focus on testing critical business logic first
- Don't chase 100% coverage at all costs
- Use coverage to find gaps, not as the only quality metric
- Combine with other quality measures (code review, static analysis)
Coverage Report Formats
- LCOV: Standard format used by many tools
- JSON: Machine-readable format for processing
- Clover XML: PHP and other language support
- JaCoCo XML: Java ecosystem standard
