Jest Coverage Comment

A GitHub Action that adds Jest test coverage reports as comments to your pull requests, helping you track and improve test coverage with visual feedback.

🎯 Features

📊 Visual Coverage Reports - Automatically comments on PRs with detailed coverage tables
🏷️ Coverage Badges - Dynamic badges showing coverage percentage with color coding
📈 Test Statistics - Shows passed, failed, skipped tests with execution time via JUnit XML
🔗 Direct File Links - Click to view uncovered lines directly in your repository
📁 Multiple Reports - Support for monorepo with multiple coverage reports
🎨 Customizable - Flexible titles, badges, and display options
📝 Multi-Format Support - Works with JSON summary, console output, and JUnit XML
🚀 Smart Updates - Updates existing comments instead of creating duplicates

📋 Table of Contents

Click to expand

Jest Coverage Comment

🚀 Quick Start

Add this action to your workflow:

- name: Jest Coverage Comment
  uses: MishaKav/jest-coverage-comment@main

📖 Complete workflow example

name: Jest Coverage Comment
on:
  pull_request:
    branches:
      - '*'

permissions:
  contents: read
  pull-requests: write

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '18'
          cache: 'npm'

      - name: Install dependencies
        run: npm ci

      - name: Run tests with coverage
        run: npx jest --coverage --coverageReporters json-summary

      - name: Jest Coverage Comment
        uses: MishaKav/jest-coverage-comment@main

⚙️ Configuration

Inputs

📝 Core Inputs

Name	Required	Default	Description
`github-token`	✓	`${{github.token}}`	GitHub API Access Token
`issue-number`			Pull request number to comment on (required for workflow_dispatch/workflow_run events)
`coverage-summary-path`		`./coverage/coverage-summary.json`	The location of the coverage-summary of Jest
`junitxml-path`			The location of the junitxml path (npm package `jest-junit` should be installed)
`coverage-path`			The location of the coverage.txt (Jest console output)

🎨 Display Options

Name	Default	Description
`title`		Main title for the comment
`summary-title`		Title for the coverage summary
`badge-title`	`Coverage`	Title for the badge icon
`junitxml-title`		Title for summary for junitxml
`coverage-title`	`Coverage Report`	Title for the coverage report
`hide-summary`	`false`	Hide coverage summary report
`hide-comment`	`false`	Hide the whole comment (use when you need only the `output`)
`remove-links-to-files`	`false`	Remove links to files (useful when summary-report is too big)
`remove-links-to-lines`	`false`	Remove links to lines (useful when summary-report is too big)

🔧 Advanced Options

Name	Default	Description
`create-new-comment`	`false`	When false, will update the same comment, otherwise will publish new comment on each run
`unique-id-for-comment`		When running in a matrix, pass the matrix value, so each comment will be updated its own comment
`coverage-path-prefix`		Prefix for path when link to files in comment
`report-only-changed-files`	`false`	Show in report only changed files for this commit, and not all files
`multiple-files`		You can pass array of `json-summary.json` files and generate single comment with table of results Single line should look like `Title1, ./path/to/json-summary.json`
`multiple-junitxml-files`		You can pass array of `junit.xml` files and generate single comment with table of results Single line should look like `Title1, ./path/to/junit.xml`

Outputs

📤 Available Outputs

Name	Example	Description
`coverage`	`78`	Percentage of the coverage, get from `coverage-summary.json`
`color`	`yellow`	Color of the percentage. You can see the whole list of badge colors
`summaryHtml`	`...`	Markdown table with summary. See the result examples
`tests`	`9`	Total number of tests, get from `junitxml`
`skipped`	`0`	Total number of skipped tests, get from `junitxml`
`failures`	`0`	Total number of tests with failures, get from `junitxml`
`errors`	`0`	Total number of tests with errors, get from `junitxml`
`time`	`2.883`	Seconds that took to run all the tests, get from `junitxml`
`lines`	`71`	Lines covered, get from Jest text report
`branches`	`100`	Branches covered, get from Jest text report
`functions`	`28`	Functions covered, get from Jest text report
`statements`	`100`	Statements covered, get from Jest text report

📚 Usage Examples

Basic Usage

Standard PR Comment

name: Jest Coverage Comment
on:
  pull_request:
jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Install dependencies
        run: npm ci
      - name: Run tests with coverage
        run: npx jest --coverage --coverageReporters json-summary
      - name: Jest Coverage Comment
        uses: MishaKav/jest-coverage-comment@main

This will create a comment showing coverage percentage with a badge and summary table.

Complete Configuration

Example showing all available parameters

- name: Jest Coverage Comment
  uses: MishaKav/jest-coverage-comment@main
  with:
    github-token: ${{ secrets.GITHUB_TOKEN }}
    coverage-summary-path: ./coverage/coverage-summary.json
    title: My Jest Coverage Comment
    summary-title: My Summary Title
    badge-title: Coverage
    hide-comment: false
    create-new-comment: false
    hide-summary: false
    remove-links-to-files: false
    remove-links-to-lines: false
    junitxml-title: My JUnit Title
    junitxml-path: ./coverage/junit.xml
    coverage-title: My Coverage Title
    coverage-path: ./coverage.txt
    coverage-path-prefix: src/
    report-only-changed-files: false

Coverage Summary Report

Generate summary from JSON coverage report

Configure Jest to generate JSON summary:

// jest.config.js
module.exports = {
  collectCoverage: true,
  coverageReporters: ['json-summary', 'text', 'html'],
  coverageDirectory: 'coverage',
}

Workflow:

- name: Run tests
  run: npx jest --coverage

- name: Jest Coverage Comment
  uses: MishaKav/jest-coverage-comment@main
  with:
    coverage-summary-path: ./coverage/coverage-summary.json

Output: Badge with coverage percentage and summary table showing file-by-file coverage.

Coverage Console Report

Generate report from Jest console output with file links

- name: Run tests
  run: npx jest --coverage | tee ./coverage.txt && exit ${PIPESTATUS[0]}

- name: Jest Coverage Comment
  uses: MishaKav/jest-coverage-comment@main
  with:
    coverage-path: ./coverage.txt
    coverage-title: Detailed Coverage Report

Output: Expandable section with detailed coverage report, including clickable links to files and specific uncovered lines.

JUnit Test Report

Add test results with jest-junit package

Install jest-junit:

npm install --save-dev jest-junit

Configure Jest:

// jest.config.js
module.exports = {
  reporters: [
    'default',
    ['jest-junit', { outputDirectory: 'coverage', outputName: 'junit.xml' }],
  ],
}

Workflow:

- name: Run tests
  run: npx jest --coverage

- name: Jest Coverage Comment
  uses: MishaKav/jest-coverage-comment@main
  with:
    junitxml-path: ./coverage/junit.xml
    junitxml-title: Test Results

Output: Table showing tests count, skipped, failures, errors, and execution time.

Multiple Files (Monorepo)

Generate combined report for multiple packages

- name: Run tests for all packages
  run: |
    cd packages/frontend && npm test -- --coverage --coverageDirectory ../../coverage/frontend
    cd packages/backend && npm test -- --coverage --coverageDirectory ../../coverage/backend
    cd packages/shared && npm test -- --coverage --coverageDirectory ../../coverage/shared

- name: Jest Coverage Comment
  uses: MishaKav/jest-coverage-comment@main
  with:
    multiple-files: |
      Frontend, ./coverage/frontend/coverage-summary.json
      Backend, ./coverage/backend/coverage-summary.json
      Shared Utils, ./coverage/shared/coverage-summary.json
    multiple-junitxml-files: |
      Frontend Tests, ./coverage/frontend/junit.xml
      Backend Tests, ./coverage/backend/junit.xml
      Shared Tests, ./coverage/shared/junit.xml

Output: Combined table showing coverage and test results for all packages.

Matrix Strategy

Multiple Node.js versions with separate comments

strategy:
  matrix:
    node-version: [16, 18, 20]

steps:
  - uses: actions/checkout@v4
  - uses: actions/setup-node@v4
    with:
      node-version: ${{ matrix.node-version }}
  - run: npm ci
  - run: npm test -- --coverage
  - name: Jest Coverage Comment
    uses: MishaKav/jest-coverage-comment@main
    with:
      unique-id-for-comment: node-${{ matrix.node-version }}
      title: Coverage Report (Node.js ${{ matrix.node-version }})

Output: Separate coverage comments for each Node.js version, each updating independently.

Workflow Dispatch Support

Manual coverage reporting with issue number

name: Manual Coverage Report
on:
  workflow_dispatch:
    inputs:
      pr_number:
        description: 'Pull Request number'
        required: true
        type: string

jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Install dependencies
        run: npm ci
      - name: Run tests with coverage
        run: npx jest --coverage --coverageReporters json-summary
      - name: Jest Coverage Comment
        uses: MishaKav/jest-coverage-comment@main
        with:
          issue-number: ${{ github.event.inputs.pr_number }}

Usage: Manually trigger this workflow and provide a PR number to get coverage comments on that specific pull request.

Output: Coverage comment will be posted to the specified pull request, even when not triggered by the PR itself.

Changed Files Only

Show coverage only for files changed in the PR

- name: Jest Coverage Comment
  uses: MishaKav/jest-coverage-comment@main
  with:
    report-only-changed-files: true
    title: Coverage for Changed Files

Output:

In PR: Shows coverage only for files modified in the PR
No changes: Shows message "report-only-changed-files is enabled. No files were changed in this commit :)"

Note: Only works with pull_request and push events.

Auto-Update README Badge

Update coverage badge in README without commits

name: Update Coverage Badge
on:
  push:
    branches: [main]

jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm ci
      - run: npm test -- --coverage

      - name: Jest Coverage Comment
        id: coverage
        uses: MishaKav/jest-coverage-comment@main
        with:
          hide-comment: true

      - name: Dynamic Badges
        if: github.ref == 'refs/heads/main'
        uses: Schneegans/[email protected]
        with:
          auth: ${{ secrets.GIST_SECRET }}
          gistID: your-gist-id-here
          filename: coverage.json
          label: Coverage
          message: ${{ steps.coverage.outputs.coverage }}%
          color: ${{ steps.coverage.outputs.color }}

🔬 Advanced Features

📊 Using Output Variables

- name: Jest Coverage Comment
  id: coverage
  uses: MishaKav/jest-coverage-comment@main

- name: Dynamic Badges
  uses: Schneegans/[email protected]
  with:
    auth: ${{ secrets.GIST_SECRET }}
    gistID: your-gist-id
    filename: coverage.json
    label: Coverage
    message: ${{ steps.coverage.outputs.coverage }}%
    color: ${{ steps.coverage.outputs.color }}

- name: Fail if coverage too low
  if: ${{ steps.coverage.outputs.coverage < 80 }}
  run: |
    echo "Coverage is below 80%!"
    exit 1

⚡ Performance Optimization

For large coverage reports that might exceed GitHub's comment size limits:

- name: Jest Coverage Comment
  uses: MishaKav/jest-coverage-comment@main
  with:
    hide-summary: true # Show only badge and test results
    report-only-changed-files: true # Only show changed files
    remove-links-to-files: true # Remove clickable file links
    remove-links-to-lines: true # Remove clickable line number links

Link Removal Options:

remove-links-to-files: true - Removes clickable links to files. Instead of [example.js](link), shows plain example.js
remove-links-to-lines: true - Removes clickable links to line numbers. Instead of [14-18](link), shows plain 14-18

These options significantly reduce comment size while preserving all coverage information.

🎨 Badge Colors

Coverage badges automatically change color based on the percentage:

Coverage	Badge	Color
0-40%		Red
40-60%		Orange
60-80%		Yellow
80-90%		Green
90-100%		Bright Green

📸 Result Examples

View example outputs

Complete Comment Example

My Jest Coverage Comment

My Summary Title

Lines Statements Branches Functions

76.74% (33/43) 33.33% (2/6) 100% (0/0)

My JUnit Title

Tests Skipped Failures Errors Time

6 0 💤 0 ❌ 0 🔥 1.032s ⏱️

My Coverage Title (78%)
File % Stmts % Branch % Funcs % Lines Uncovered Line #s
All files 76.74 100 33.33 78.57
src 75.67 100 40 75.67
controller.js 63.63 100 50 63.63 14–18
index.js 85.71 100 0 85.71 9
router.js 100 100 100 100
service.js 69.23 100 50 69.23 16–20
src/utils 83.33 100 0 100
config.js 100 100 100 100
utils.js 75 100 0 100

Coverage Summary Report

Coverage Console Report

JUnit Test Report

Multiple Files (Monorepo)

🔧 Troubleshooting

Common Issues and Solutions

Comment Not Appearing

Problem: The action runs successfully but no comment appears on the PR.

Solutions:

Ensure proper permissions are set:

permissions:
  contents: read
  pull-requests: write

Check if hide-comment is set to false
Verify the action is running on supported events (pull_request, push, workflow_dispatch, workflow_run)
For workflow_dispatch or workflow_run events, ensure issue-number input is provided

Coverage Report Too Large

Problem: "Comment is too long (maximum is 65536 characters)"

Solutions:

Use report-only-changed-files: true
Set hide-summary: true to show only badge
Use remove-links-to-files: true to remove clickable file links
Use remove-links-to-lines: true to remove clickable line number links
Use ["text-summary", { "skipFull": true }] in Jest coverage reporters to skip fully covered files

Coverage Shows 0%

Problem: Jest not collecting coverage for your files

Solutions:

// Check collectCoverageFrom in jest.config.js
collectCoverageFrom: ['src/**/*.{js,ts}', '!src/**/*.test.{js,ts}']

Files Not Found

Problem: "No such file or directory" errors

Solutions:

Use absolute paths or paths relative to $GITHUB_WORKSPACE
Check that coverage files are generated before the action runs
Verify Jest configuration generates required files

Wrong File Links

Problem: Links in the coverage report point to wrong files or 404

Solutions:

Use coverage-path-prefix if your test paths differ from repository structure
Ensure the action runs on the correct commit SHA

Workflow Dispatch Events

Problem: Need to trigger coverage reporting on specific PRs manually

Solutions:

Use issue-number input to specify the target PR:

- name: Jest Coverage Comment
  uses: MishaKav/jest-coverage-comment@main
  with:
    issue-number: 123 # Replace with actual PR number

For workflow_dispatch, add input parameter:

on:
  workflow_dispatch:
    inputs:
      pr_number:
        description: 'Pull Request number'
        required: true

🤝 Contributing

We welcome all contributions! Please feel free to submit pull requests or open issues for bugs, feature requests, or improvements.

Development Setup

# Clone the repository
git clone https://github.com/MishaKav/jest-coverage-comment.git
cd jest-coverage-comment

# Install dependencies
npm install

# Run tests
npm test

# Build the action
npm run build

# Package for distribution
npm run package

👥 Contributors

📄 License

🔗 Similar Actions

For Python projects using pytest: Check out pytest-coverage-comment - a similar action for Python test coverage with pytest.

If you find this action helpful, please consider giving it a ⭐ on GitHub!

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	76.74	100	33.33	78.57
src	75.67	100	40	75.67
controller.js	63.63	100	50	63.63	14–18
index.js	85.71	100	0	85.71	9
router.js	100	100	100	100
service.js	69.23	100	50	69.23	16–20
src/utils	83.33	100	0	100
config.js	100	100	100	100
utils.js	75	100	0	100

Jest Coverage Comment

🎯 Features

📋 Table of Contents

🚀 Quick Start

⚙️ Configuration

Inputs

Outputs

📚 Usage Examples

Basic Usage

Complete Configuration

Coverage Summary Report

Coverage Console Report

JUnit Test Report

Multiple Files (Monorepo)

Matrix Strategy

Workflow Dispatch Support

Changed Files Only

Auto-Update README Badge

🔬 Advanced Features

🎨 Badge Colors

📸 Result Examples

Complete Comment Example

My Jest Coverage Comment

My Summary Title

My JUnit Title

Coverage Summary Report

Coverage Console Report

JUnit Test Report

Multiple Files (Monorepo)

🔧 Troubleshooting

Comment Not Appearing

Coverage Report Too Large

Coverage Shows 0%

Files Not Found

Wrong File Links

Workflow Dispatch Events

🤝 Contributing

Development Setup

👥 Contributors

📄 License

🔗 Similar Actions

Contributors10 (10)

Resources

About

Tags

Contributors10 (10)

Resources

Contributors (10)

Contributors (10)