GitHub App Integration (Optional)

Install GitHub App Integration (https://github.com/apps/codecov).

Generate report

Have a try whether the coverage report could be generated.

$ test --ci --coverage --watchAll=false
$ ls -1 coverage
clover.xml
coverage-final.json
lcov-report
lcov.info

Add to package.json

{
  "scripts": {
    "report": "react-scripts test --ci --coverage --watchAll=false && npx codecov -F unittests"
  }
}

Set codecov.io upload token

Set your codecov.io upload token to Travis CI.

Find your token in codecov.io first.

https://app.codecov.io/gh/your-name/your-repo

Then put it in the “Environment Variables - Settings” of your project on Travis CI. (https://www.travis-ci.com/github/your-name/your-repo/settings)

CODECOV_TOKEN=123456

Add npm run report to travis.yml

script:
  - npm test
  # Generate code coverage report and upload to codecov.io
  - npm run eport
  - npm run build

Show badge on the first page of the GitHub repo

Copy markdown of badge

https://app.codecov.io/gh/your-user-name/your-repo-name/settings/badge

Update README.md

# Your Repo Name [![codecov](https://codecov.io/gh/your-user-name/your-repo-name/branch/master/graph/badge.svg?token=123456)](https://codecov.io/gh/your-user-name/your-repo-name)

Install Chrome extension to show code coverage information from Codecov on GitHub

https://github.com/codecov/sourcegraph-codecov/blob/master/README.md

References