test-coverage_skill

Overview

This skill measures and improves test coverage by finding untested code paths and prioritizing high-risk areas for testing. It helps teams focus testing effort where it matters most, turning raw coverage numbers into concrete actions that reduce risk and increase reliability.

How this skill works

The skill runs coverage tools against your test suite, parses line, branch, and function coverage reports, and highlights uncovered code paths that are likely to contain bugs. It performs a gap analysis to rank uncovered areas by risk and complexity, then produces a prioritized plan for writing tests and validating improvements.

When to use it

• Evaluating overall quality and completeness of a test suite
• Before a release to ensure critical paths are protected
• When integrating new features that touch core logic
• To allocate testing resources effectively in large codebases
• During refactoring to ensure behavior remains covered

Best practices

• Aim for 80%+ coverage on critical business logic rather than an arbitrary project-wide target
• Prioritize tests for error handling, edge cases, and input validation before low-risk UI code
• Write meaningful assertions that validate behavior, not just lines executed
• Iterate: re-run coverage after adding tests to confirm improvements
• Avoid chasing 100% coverage on trivial or generated code

Example use cases

• A CI job that fails the build if critical modules drop below a coverage threshold
• A sprint planning session where uncovered high-risk functions are added to the backlog
• Targeted test writing after a code audit reveals low branch and error-path coverage
• Risk-based testing for a release: focus efforts on components with highest business impact
• Regression protection: add tests for uncovered bugs discovered in production