test-coverage-analyzer

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Translated

Analyzes test coverage reports, identifies gaps, and recommends priority areas for testing. Use when reviewing coverage, finding untested code, or planning test improvements.

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NPX Install

npx skill4agent add armanzeroeight/fastagent-plugins test-coverage-analyzer

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Translated version includes tags in frontmatter
test-coverage-analysistesting-gap-identificationtest-prioritizationcoverage-metricstesting-tools

SKILL.md Content

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Test Coverage Analyzer

Analyze test coverage and identify testing gaps.

Quick Start

Run coverage and analyze results:
bash
# JavaScript/TypeScript
npm test -- --coverage

# Python
pytest --cov=src --cov-report=term-missing

# Go
go test -cover ./...

Instructions

Step 1: Generate Coverage Report

JavaScript/TypeScript (Jest):
bash
npm test -- --coverage --coverageReporters=text --coverageReporters=lcov
JavaScript/TypeScript (Vitest):
bash
vitest run --coverage
Python (pytest):
bash
pytest --cov=src --cov-report=html --cov-report=term-missing
Go:
bash
go test -coverprofile=coverage.out ./...
go tool cover -html=coverage.out

Step 2: Analyze Coverage Metrics

Review these key metrics:
  • Line coverage: Percentage of lines executed
  • Branch coverage: Percentage of conditional branches tested
  • Function coverage: Percentage of functions called
  • Statement coverage: Percentage of statements executed
Target thresholds:
  • Critical code: 80%+ coverage
  • Standard code: 60%+ coverage
  • UI/Config: 40%+ coverage

Step 3: Identify Gaps

Look for:
  • Uncovered functions: Functions with 0% coverage
  • Partial coverage: Functions with <50% coverage
  • Missing branches: Untested if/else paths
  • Error paths: Untested catch blocks
  • Edge cases: Boundary conditions not tested

Step 4: Prioritize Testing

High Priority (test first):
  • Business logic with 0% coverage
  • Security-critical functions
  • Payment/transaction code
  • Data validation logic
  • Error handling paths
Medium Priority (test next):
  • API endpoints
  • Database operations
  • Utility functions
  • Configuration logic
Low Priority (test if time permits):
  • Simple getters/setters
  • UI presentation logic
  • Type definitions
  • Generated code

Step 5: Create Action Plan

For each gap:
  1. Identify the untested code
  2. Determine test type needed (unit/integration/e2e)
  3. Estimate effort (small/medium/large)
  4. Assign priority (high/medium/low)
  5. Create test implementation tasks

Common Patterns

Pattern: Find untested files
bash
# Jest
npm test -- --coverage --collectCoverageFrom='src/**/*.{js,ts}' --coverageThreshold='{"global":{"lines":0}}'

# pytest
pytest --cov=src --cov-report=term-missing | grep "0%"
Pattern: Check specific module
bash
# Jest
npm test -- path/to/module --coverage

# pytest
pytest tests/test_module.py --cov=src.module --cov-report=term-missing
Pattern: Enforce coverage thresholds
json
// package.json (Jest)
{
  "jest": {
    "coverageThreshold": {
      "global": {
        "branches": 70,
        "functions": 70,
        "lines": 70,
        "statements": 70
      }
    }
  }
}

Advanced

For detailed information, see:
  • Coverage Tools - Tool-specific configuration and usage
  • Testing Patterns - Common testing patterns and best practices