Coverage

What Is Coverage?

Coverage is a specialized Claude Code skill designed to streamline and automate test coverage analysis within modern web application projects. The skill provides an intelligent workflow for identifying test coverage gaps by mapping all testable surfaces in your application—routes, components, API endpoints, and user flows—and cross-referencing them against your existing test suite.

Using Coverage, engineering teams can comprehensively answer questions such as "What’s not tested?", "Where are the coverage gaps?", and "What needs additional testing?" in a systematic, repeatable manner. The skill leverages structured code analysis to scan application codebases and test files, producing actionable insights and detailed matrices that reveal both strong and weak areas in your testing strategy.

With its focus on automation and workflow integration, Coverage minimizes manual effort and reduces the risk of untested critical paths.

Why Use Coverage?

Maintaining robust test coverage is essential for ensuring application reliability, reducing the risk of production incidents, and enabling confident refactoring. However, as applications grow in complexity, it becomes increasingly difficult to manually track which parts of the codebase are adequately tested and which are not. Teams often face the following challenges:

• Unintentional Gaps: Business-critical routes or components may lack tests due to oversight or legacy code.
• Incomplete Flows: Multi-step user journeys (such as checkout or onboarding) may be partially tested, leaving edge cases exposed.
• Manual Tracking: Relying on spreadsheets or ad-hoc documentation to track coverage is error-prone and quickly becomes outdated.
• Lack of Visibility: Engineers may not know which API endpoints or components are entirely untested or insufficiently tested. The Coverage skill addresses these issues by automating the discovery and analysis process. It offers development teams greater clarity, helps prioritize test writing efforts, and directly contributes to higher software quality.

How to Get Started Coverage can be integrated into your workflow with minimal setup.

To use the skill:

1. Clone the Skill Repository Retrieve the skill from the official source:

git clone https://github.com/alirezarezvani/claude-skills.git

Navigate to the engineering-team/playwright-pro/skills/coverage directory. 2. Configure the Skill Ensure your application codebase and test suite follow standard structures:

• Application routes/pages (e.g., Next.js app/, React Router, Vue Router) - Component directories - API route files or backend controllers - Test files named with .spec.ts or .spec.js 3. Run the Coverage Analysis Utilize the skill within Claude Code to trigger coverage analysis. For example, prompt:

Analyze test coverage for our application.

The skill will automatically:

• Map all pages, components, endpoints, and key user flows.
• Scan test files to determine which areas are covered.
• Generate a detailed coverage matrix.

4. Review the Coverage Matrix The output will include a table similar to the following:

| Area | Route | Tests | Status | |-----------|-------------------|-------|-----------------------------| | Auth | /login | 5 | Covered | | Auth | /register | 0 | Missing | | Dashboard | /dashboard | 3 | Partial (no error states)|

Prioritize and Address Gaps Use the matrix to identify untested or partially tested areas and plan additional test writing as needed.

Key Features Coverage stands out with several key capabilities:

• Automated Route and Component Mapping: Scans route definitions and component directories to catalog all user-facing application surfaces.
• Test File Analysis: Inspects .spec.ts and .spec.js files to extract coverage information, including:
• Pages visited (e.g., await page.goto('/login')) - Components interacted with (e.g., await page.locator('[data-testid="submit"]')) - API endpoints mocked or hit during tests - User Flow Identification: Automatically detects critical user journeys such as authentication, checkout, and onboarding, mapping multi-step workflows for thorough coverage analysis.
• Coverage Matrix Generation: Produces a detailed matrix highlighting covered, missing, and partially tested areas.
• Integration with Exploration Tools: Leverages subagents like Explore to deepen codebase understanding and ensure comprehensive mapping.

Example:

Mapping Routes and Tests

// Example: Extracting covered routes from Playwright test test('Login page loads', async ({ page }) => { await page.goto('/login'); // ...test logic... });

Coverage parses such statements to map the /login route as tested, and cross-references all defined routes to highlight any missing coverage.

Best Practices

To maximize the value of Coverage:

• Maintain Consistent Naming: Ensure test files follow standard conventions (*.spec.ts/*.spec.js) for accurate detection.
• Document User Flows: Clearly define critical workflows in your codebase or documentation to help Coverage identify and map them.
• Review Matrices Regularly: Integrate coverage analysis into your development process, such as during sprint reviews or before releases.
• Address Partial Coverage: Pay attention to areas marked as "Partial," as they may lack tests for edge cases or error states.
• Automate in CI: Where possible, trigger Coverage as part of your continuous integration pipelineto ensure up-to-date insights and early detection of coverage regressions.

Important Notes

• Language and Framework Support: Coverage is optimized for JavaScript/TypeScript projects using frameworks like React, Next.js, and Node.js, but can be adapted to other stacks with similar file structures.
• Custom Test Patterns: If your project uses non-standard test file naming or organization, update the configuration to ensure all relevant tests are included in the analysis.
• Limitations: Automated mapping may not capture dynamically generated routes or highly abstracted user flows. Manual review is recommended for complex applications.
• Security and Privacy: The skill analyzes code and test files locally; ensure sensitive information is handled according to your organization’s policies.

By integrating Coverage into your workflow, your team can systematically improve test completeness, reduce risk, and foster a culture of quality. Continuous use of this skill helps maintain high standards as your application evolves.