covet

Cover it!

covet reads version control diffs and Go coverage files to generate useful stats about their intersection. Currently displays coverage percentage of the diff and highlights any new, uncovered lines.

go install github.com/johnstarich/go/covet/cmd/covet@latest
covet -help

git diff HEAD~10...HEAD > my.diff
go test -coverprofile=cover.out ./...

covet -diff-file my.diff -cover-go cover.out
#  ... includes diff and coverage intersection ...
# Total diff coverage:  84.1%
#
# Diff coverage is below target. Add tests for these files:
#
# ┌─────────┬──────────────┬────────────────────────────────────────────┐
# │ LINES   │ COVERAGE     │ FILE                                       │
# ├─────────┼──────────────┼────────────────────────────────────────────┤
# │ 239/279 │  85.7% ████▎ │ diffcover/cmd/diffcover/run.go             │
# │  16/42  │  38.1% █▉    │ diffcover/cmd/diffcover/coverage_status.go │
# └─────────┴──────────────┴────────────────────────────────────────────┘

Still experimental: Future releases may contain breaking changes.

Thoughts or questions? Please open an issue to discuss.

Integrate with GitHub

Covet includes an automatic GitHub Actions integration and opt-in GitHub comment summary reports.

To enable comment summaries, you need to set a few additional flags.

Here's an example using GitHub Actions:

  test:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
    - uses: actions/checkout@v3
    - name: checkout
      run: |
        commits=${{ github.event.pull_request.commits }}
        if [[ -n "$commits" ]]; then
          # Prepare enough depth for diffs with master
          git fetch --depth="$(( commits + 1 ))"
        fi
    - uses: actions/setup-go@v3
      with:
        go-version: 1.16.x
    - name: Test
      run: |
        git diff origin/master | \
            covet \
                -diff-file - \
                -cover-go ./cover.out \
                -show-diff-coverage \
                -gh-token "$GITHUB_TOKEN" \
                -gh-issue "github.com/${GITHUB_REPOSITORY}/pull/${ISSUE_NUMBER}" 
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

And here's an example using environment variables from Travis CI:

git diff origin/master | \
    covet \
        -diff-file - \
        -cover-go ./cover.out \
        -show-diff-coverage \
        -gh-token "$GITHUB_TOKEN" \
        -gh-issue "github.com/${TRAVIS_PULL_REQUEST_SLUG}/pull/${TRAVIS_PULL_REQUEST}"