How to view a coverage report from GitHub Actions

GitHub Actions workflows generate coverage reports as downloadable artifacts. When your CI uploads a lcov.info file, you can download it and view the per-file breakdown without checking out the branch or running the tests locally — useful for reviewing coverage on a colleague's pull request.

Step-by-step guide

1. Download the coverage artifact: In GitHub, open the Actions tab, click the workflow run, scroll to Artifacts, and download the coverage artifact. Extract the zip to find lcov.info.
2. Upload to the LCOV viewer: Drag the lcov.info file onto quickhelp.dev/lcov-viewer. Coverage data appears within seconds — no local test run needed.
3. Review PR coverage gaps: Compare the file list against the changed files in the PR. Files changed in the PR that appear red or yellow in the viewer are the ones that need more test coverage.

Frequently asked questions

How do I add LCOV artifact upload to my GitHub Actions workflow?

Add this step after your test command: uses: actions/upload-artifact@v4 with name: coverage, path: coverage/lcov.info. This makes the file downloadable from the Actions UI.

Can I compare coverage between two branches?

Download the lcov.info artifact from each branch's latest CI run and open them in separate browser tabs. The viewer shows one report at a time.