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test-coverage-analysis

Analyzes Istanbul, lcov, and Jest coverage reports to identify gaps and prioritize testing efforts.

1|Updated Oct 11, 2025
Search Tags:#typescript#testing#jest#gap analysis#test coverage#risk assessment#istanbul
One-click install
npx skills add https://github.com/codewizwit/human-in-the-loop --skill test-coverage-analysis-codewizwit
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: test-coverage-analysis
Source: https://github.com/codewizwit/human-in-the-loop/tree/main/lib/skills/test-coverage-analysis
Command: npx skills add https://github.com/codewizwit/human-in-the-loop --skill test-coverage-analysis-codewizwit

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? Teams often have coverage reports full of numbers but no clear sense of which gaps actually matter. This Skill turns raw coverage data into a risk-ranked, prioritized action plan so testing effort goes toward the code that carries the most business risk. ## Core Features & Use Cases - Coverage Gap Analysis: Parses Istanbul/NYC JSON, lcov summaries, and Jest output to find files below target thresholds across statements, branches, functions, and lines. - Risk-Based Prioritization: Assesses business impact and security implications of uncovered code, ranking gaps as P0/P1/P2 rather than by percentage alone. - Actionable Recommendations: Generates specific test cases with describe/it blocks, effort estimates, and a phased roadmap to reach coverage targets. - Use Case: A team at 67% coverage needs to reach 80% before release. The Skill identifies the auth service and payments module as critical gaps and produces a two-week plan with concrete tests to close them. ## Quick Start Ask the assistant to analyze your coverage report and create a prioritized plan to reach your target coverage percentage.

Frequently Asked Questions about test-coverage-analysis

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I analyze a Jest coverage report to find gaps?▼

Provide the Jest coverage output or the path to your coverage directory, and the analysis parses statement, branch, function, and line metrics to list files below your target threshold. Each gap is ranked by business risk with recommended test cases.

What coverage formats does this analysis support?▼

It supports Istanbul/NYC JSON reports, lcov summary files, and Jest coverage output. You can paste the data directly or provide a file path, and it can also auto-discover coverage files in coverage/ or .nyc_output/ directories.

How do I prioritize which tests to write first?▼

Prioritization is based on business impact and risk level rather than raw percentage. Security-sensitive code like authentication and business-critical paths like payments are ranked P0, while trivial code such as simple getters is excluded from recommendations.

Does this work with Angular and NestJS projects?▼

Yes, the analysis accounts for framework-specific testing patterns in Angular and NestJS codebases. It recognizes common structures like services, guards, and components when assessing risk and suggesting test cases.

Should I aim for 100% test coverage?▼

No, the analysis explicitly avoids recommending 100% coverage because returns diminish past roughly 90%. It focuses on meaningful coverage of high-risk code and flags branch coverage gaps, which are often the most neglected metric.

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