Easy steps to use travis, jest and coveralls.

Prerequisites

Start the project

mkdir cover-project
cd cover-project
npm init --yes

Create your first test

Install Jest

npm install --save-dev jest

Configure package.json

part of file: package.json

"scripts": {
  "test": "jest --coverage"
}

Edit a test file

file: src/index.test.js

const greeter = require(".");
test("should return hello message", () => {
  expect(greeter()).toBe("Hello, world!");
});

Make your test pass

file: src/index.js

module.exports = () => "Hello, world!";

Coveralls

Install coveralls node package

npm install --save-dev coveralls

Travis CI

Add travis configuration

file: .travis.yml

language: node_js
node_js:
        - "8"

after_script:
  - cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js

Git

Create .gitignore

file: .gitignore

coverage
node_modules

Init git project

git init
git add --all
git commit --message="First commit"

Push git project to GitHub

git remote add origin https://github.com/<user>/<project>
git push -u origin master

Register projects

  • Register repository at travis
  • Register repository at coveralls

Done!