Test Coverage Analysis Skill

You are the test-coverage skill. When invoked, you run appropriate coverage tools based on project language and generate structured coverage reports.

When to Invoke This Skill

Invoke this skill when:

• •Tech Lead is reviewing test files
• •Before approving code changes or pull requests
• •Developer claims "added tests"
• •Before merging to main branch
• •Checking if coverage meets project standards

Do NOT invoke when:

• •No tests exist in the project
• •Just viewing code (not reviewing for approval)
• •Emergency hotfix (skip coverage check)
• •Documentation-only changes

Your Task

When invoked:

1. •Execute the test coverage script
2. •Read the generated coverage report
3. •Return a summary to the calling agent

Step 1: Execute Coverage Script

Use the Bash tool to run the pre-built coverage script.

On Unix/macOS:

bash .claude/skills/test-coverage/scripts/coverage.sh

On Windows (PowerShell):

pwsh .claude/skills/test-coverage/scripts/coverage.ps1

Cross-platform detection: Check if running on Windows ($env:OS contains "Windows" or uname doesn't exist) and run the appropriate script.

This script will:

• •Detect project language (Python, JavaScript, Go, Java)
• •Auto-install required tools (pytest-cov, jest, etc.) if needed
• •Run coverage analysis
• •Parse results
• •Generate bazinga/artifacts/{SESSION_ID}/skills/coverage_report.json

Step 2: Read Generated Report

Use the Read tool to read:

bazinga/artifacts/{SESSION_ID}/skills/coverage_report.json

Extract key information:

• •overall_coverage - Total line coverage percentage
• •files_below_threshold - Files with coverage < 80%
• •critical_uncovered_paths - Important code without tests

Step 3: Return Summary

Return a concise summary to the calling agent:

Test Coverage Report:
- Overall coverage: {percentage}%
- Files below 80% threshold: {count} files
- Critical areas with low coverage:
  - {file1}: {percentage}% coverage
  - {file2}: {percentage}% coverage

Details saved to: bazinga/artifacts/{SESSION_ID}/skills/coverage_report.json

Example Invocation

Scenario: Reviewing PR with New Authentication Tests

Input: Tech Lead reviewing PR #123 with new auth module tests

Expected output:

Test Coverage Report:
- Overall coverage: 78%
- Files below 80% threshold: 2 files
- Critical areas with low coverage:
  - auth.py: 68% coverage (uncovered lines: 45-52, 89-103)
  - payment.py: 52% coverage (uncovered lines: 23, 45-78)

Details saved to: bazinga/artifacts/{SESSION_ID}/skills/coverage_report.json

Scenario: Full Coverage Achieved

Input: Tech Lead final review before merge

Expected output:

Test Coverage Report:
- Overall coverage: 94%
- Files below 80% threshold: 0 files
- All critical code paths covered

Details saved to: bazinga/artifacts/{SESSION_ID}/skills/coverage_report.json

Error Handling

If coverage tool not installed:

• •Script attempts auto-installation
• •Falls back gracefully if installation fails
• •Returns partial report with error note

If no tests found:

• •Return: "No tests found in project. Cannot generate coverage report."

If tests fail:

• •Return: "Tests failed. Coverage report not generated. Fix failing tests first."

Notes

• •The script (260+ lines) handles all language detection and tool execution
• •Supports both bash (Linux/Mac) and PowerShell (Windows)
• •Graceful degradation when tools unavailable
• •Focuses on line coverage as primary metric
• •Excludes test files, generated code, and config from coverage analysis