AgentSkillsCN

Test Coverage Analyzer

测试覆盖率分析仪

SKILL.md

Test Coverage Analyzer

Test coverage analyzer for identifying untested code and analyzing coverage metrics.

When to Use

Use this skill when:

  • •Analyzing code coverage reports
  • •Identifying untested code paths
  • •Improving test coverage percentages
  • •Setting coverage thresholds and goals
  • •Reviewing coverage trends over time
  • •Auditing quality gates in CI/CD

Key Concepts

Coverage Types

  • •Line Coverage: Percentage of executed lines
  • •Statement Coverage: Percentage of executed statements
  • •Branch Coverage: Percentage of executed branches (if/else, switch)
  • •Function Coverage: Percentage of called functions
  • •Condition Coverage: Boolean expression outcomes

Common Tools

  • •Istanbul/nyc: JavaScript/TypeScript coverage
  • •JaCoCo: Java coverage
  • •Coverage.py: Python coverage
  • •pytest-cov: Python pytest plugin
  • •lcov: Unified coverage format
  • •Codecov: Coverage reporting service
  • •SonarQube: Code quality and coverage

Patterns and Practices

Coverage Analysis

  1. •Generate coverage report
  2. •Review overall coverage percentage
  3. •Identify low-coverage modules/files
  4. •Analyze untested code paths
  5. •Assess criticality of uncovered code
  6. •Prioritize test additions based on risk
  7. •Set coverage thresholds
  8. •Integrate into CI/CD pipeline

Best Practices

  • •Aim for 80%+ line coverage (industry standard)
  • •Prioritize coverage over complex business logic
  • •Focus on critical paths and security-sensitive code
  • •Use coverage as a guide, not a goal
  • •Combine with mutation testing for quality
  • •Track coverage trends over time
  • •Set per-module thresholds, not just global

Anti-Patterns

  • •Writing tests solely for coverage numbers
  • •Ignoring coverage for "trivial" code
  • •Setting unrealistic 100% coverage goals
  • •Focusing only on line coverage, ignoring branches

Tools by Language

JavaScript/TypeScript

bash
npx nyc npm test
npx nyc report --reporter=lcov

Python

bash
pytest --cov=src --cov-report=html
coverage report -m

Java

bash
mvn jacoco:report

CI/CD Integration

GitHub Actions

yaml
- name: Run tests with coverage
  run: npm test -- --coverage
- name: Upload coverage to Codecov
  uses: codecov/codecov-action@v3

File Patterns

Look for:

  • •**/coverage/**/*
  • •**/*.lcov
  • •**/test-results/**/*
  • •**/.nyc_output/**/*
  • •**/htmlcov/**/*

Keywords

Test coverage, code coverage, coverage analysis, coverage report, untested code, coverage metrics, coverage threshold, code quality, branch coverage, line coverage, function coverage, statement coverage, condition coverage