test-coverage

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Analyze test coverage and generate a detailed coverage report

⭐1stars🔀0forks📁View on GitHub🕐Updated Nov 22, 2025
[Testing and QA]

When & Why to Use This Skill

This Claude skill automates the analysis of software test coverage by parsing LCOV data and generating detailed, actionable reports. It helps developers visualize code quality, identify untested functions, and receive data-driven recommendations for improving test suites, ultimately ensuring more robust and reliable codebases.

Use Cases

  • Automated Quality Audits: Generate comprehensive coverage reports immediately after test execution to verify that new features or bug fixes are adequately tested.
  • Identifying Testing Gaps: Locate specific untested functions and code blocks to prioritize development efforts on high-risk, low-coverage areas.
  • Code Review Support: Supplement pull requests with detailed coverage statistics to help reviewers assess the thoroughness of the submitted tests.
  • Coverage Trend Tracking: Monitor changes in testing effectiveness over time by comparing current results with previous coverage data to prevent regressions in quality.
nametest-coverage
descriptionAnalyze test coverage and generate a detailed coverage report

Test Coverage Report Skill

This skill analyzes test coverage for the codebase and generates a detailed report.

Instructions

When this skill is invoked, you should:

  1. Parse the coverage data if it exists:

    • If it does not exist, run tests first
    • If it still does not exist, do not proceed further
    • Read the coverage file: coverage/lcov-buttercup.info
    • Parse LCOV format to extract:
      • Lines with execution counts (DA:line_number,count)
      • Total lines and covered lines
      • Coverage percentage

  2. Identify covered code sections:

    • Find which line ranges are covered (count > 0)
    • Group consecutive covered lines into ranges
    • Read the source file to identify which functions are covered

  3. Generate a comprehensive report including:

    • Test execution summary (pass/fail count, execution time)
    • Overall coverage statistics (lines covered, percentage)
    • List of tested functions with their line ranges
    • List of untested functions
    • Coverage trend if previous coverage data is available
    • Recommendations for next testing priorities

  4. Format the output with:

    • Clear sections and headers
    • Tables for statistics
    • Easy-to-read formatting using markdown

Coverage Calculation Formula

Coverage % = (Lines with count > 0) / (Total lines) * 100

Example Output Format

## Test Coverage Report

### Test Execution
- ✅ All X tests passed
- Execution time: Y ms

### Coverage Statistics
- Lines covered: X/Y (Z%)
- Previous coverage: A/B (C%)
- Change: +D lines (+E%)

### Tested Functions
1. function-name (lines X-Y) - Z lines covered
2. another-function (lines A-B) - C lines covered

### Coverage Gaps
- untested-function (lines X-Y) - D lines
- another-untested (lines A-B) - E lines

### Recommendations
The next most valuable functions to test are:
...

Notes

  • Always verify the coverage directory exists before attempting to read it
  • Handle missing or malformed coverage data gracefully
  • Provide actionable recommendations based on function importance and coverage impact