PHP Coverage Filter

• Run only the tests that cover lines that have been changed.
• View the report for only files that have been changed.

Install

Via Phive:

phive install brianhenryie/php-diff-test

composer require --dev brianhenryie/php-diff-test

Run

Requires XDEBUG_MODE=coverage.

php-diff-test filter

Prints a filter to use with PHPUnit or Codeception, so you only run tests relevant to changes in the branch you're working on.

• Run: phpunit --filter="$(php-diff-test filter)" or codecept run suitename "$(php-diff-test filter)".
• Try just php-diff-test filter to see the filter that will be applied, which is effectively php-diff-test filter --input-files <glob *.cov> --diff-from main --diff-to HEAD~0 --granularity line
• Try php-diff-test filter --diff-from HEAD~3 to print a shallower filter
• Try php-diff-test filter --granularity file to print a filter which includes all tests that cover any line in changed files (this makes the HTML report make more sense)

php-diff-test coverage

Outputs a new .cov file containing only the files whose lines have been changed in the diff. Intended to then print a HTML coverage report

• Run: php-diff-test coverage --input-files "php-coverage1.cov,php-coverage2.cov" --diff-from main --diff-to HEAD~0 --output-file diff-coverage/diff-from-to.cov
• Then to generate the new HTML report: phpcov merge ./diff-coverage --html ./diff-coverage/report. NB phpcov will merge all .cov files in the directory and subdirectories so you should set php-diff-test coverage's new .cov --output-file to be in its own directory.

How it works

Runs git diff, parses which lines have been changed, parses *.cov codecoverage files to match which tests cover those lines.

The script looks in the current working directory, its tests subfolder, and each of the tests immediate subfolders for *.cov.

It also checks tests for Codeception *.suite.y*ml files, and assumes a file named unit.cov corresponds with unit.suite.yml to determine should the output be formatted for codecept run... syntax rather than PHPUnit --filter="..." syntax.

Obviously, it's assumed you're working inside a Git repo and have previously generated code coverage (in PHP .cov format).

⚠️ This has been tested to just over 500 test cases. It will inevitably have its limits, when you should probably use groups to first generate the coverage to be filtered.

Composer Scripts

Rough notes

{
  "scripts": {
    "post-install-cmd": [
      "@install-phive-dependencies"
    ],
    "post-update-cmd": [
      "@install-phive-dependencies"
    ],
    "install-phive-dependencies": [
      "if [ -z \"$(command -v phive)\" ]; then echo \"Phive is not installed. Run 'brew install gpg phive' or see https://phar.io/.\"; exit 1; fi;",
      "phive install"
    ],
    "test-changes": [
      "if [ -z \"$(command -v ./tools/php-diff-test)\" ]; then echo \"Please install 'php-diff-test' with 'phive install'.\"; exit 1; fi;",
      "if [ \"$XDEBUG_MODE\" != \"coverage\" ]; then echo 'Run with XDEBUG_MODE=coverage composer test-changes'; exit 1; fi;",
      "phpunit --filter=\"$(./tools/php-diff-test filter --input-files tests/_reports/php.cov --granularity=line)\" --coverage-text;"
    ],
    "test-changes-report": [
      "if [ -z \"$(command -v ./tools/php-diff-test)\" ]; then echo \"Please install 'php-diff-test' with 'phive install'.\"; exit 1; fi;",
      "if [ -z \"$(command -v ./tools/phpcov)\" ]; then echo \"Please install 'phpcov' with 'phive install'.\"; exit 1; fi;",
      "if [ \"$XDEBUG_MODE\" != \"coverage\" ]; then echo 'Run with XDEBUG_MODE=coverage composer test-changes-report'; exit 1; fi;",
      "if [ -d \"tests/_reports/diff\" ]; then rm -rf tests/_reports/diff; fi;",
      "phpunit --filter=\"$(./tools/php-diff-test filter --input-files tests/_reports/php.cov --granularity file)\" --coverage-text --coverage-php tests/_reports/diff/php.cov -d memory_limit=-1;",
      "./tools/php-diff-test coverage --input-files tests/_reports/diff/php.cov --output-file tests/_reports/diff/php.cov;",
      "./tools/phpcov merge tests/_reports/diff --html tests/_reports/diff/html;",
      "open tests/_reports/diff/html/index.html"
    ],
    "test-coverage": [
      "Composer\\Config::disableProcessTimeout",
      "if [ \"$XDEBUG_MODE\" != \"coverage\" ]; then echo \"Run with 'XDEBUG_MODE=coverage composer test-coverage'\"; exit 1; fi;",
      "phpunit --coverage-text --coverage-html tests/_reports/html --coverage-clover tests/_reports/clover.xml --coverage-php tests/_reports/php.cov -d memory_limit=-1 --order-by=random",
      "php-coverage-badger tests/_reports/clover.xml .github/coverage.svg",
      "if [ $(command -v ./tools/phpcov) ]; then git diff main...head > /tmp/main.diff; ./tools/phpcov patch-coverage --path-prefix $(pwd) ./tests/_reports/php.cov /tmp/main.diff || true; fi;",
      "# Run 'open ./tests/_reports/html/index.html' to view report."
    ]
  },
  "scripts-descriptions": {
    "test-changes": "Run PHPUnit only on lines that have changed in main...HEAD",
    "test-changes-report": "Run PHPUnit only on files that have changed in main...HEAD and display the HTML report.",
    "test-coverage": "Run PHPUnit tests with coverage. Use 'XDEBUG_MODE=coverage composer test-coverage' to run, 'open ./tests/_reports/html/index.html' to view."
  }
}

GitHub Actions

Rough notes:

      - name: Install Phive tools
        uses: ngmy/phive-install-action@master

      - name: Execute tests with full code coverage report
        run: XDEBUG_MODE=coverage composer run-script test-coverage

      - name: Generate diff coverage report
        if: ${{ matrix.php-version == '8.2' && github.event_name == 'pull_request' }}
        run: |
          # Filter the code coverage report to only include the files that have changed.
          ./tools/php-diff-test coverage --input-files "tests/_reports/php.cov" --diff-from origin/main --diff-to ${{ github.event.pull_request.head.sha }} --output-file tests/_reports/branch/branch.cov
          # Generate the HTML report for the filtered code coverage report.
          ./tools/phpcov merge tests/_reports/branch/ --html tests/_reports/diff/html

      - name: Attach diff coverage report artifact to workflow run
        id: artifact-upload-step
        if: ${{ matrix.php-version == '8.2' && github.event_name == 'pull_request' }}
        uses: actions/upload-artifact@v4
        with:
          name: coverage-report
          path: tests/_reports/diff/html
          retention-days: 90

      # URL is still private.
      - name: Output artifact URL
        if: ${{ matrix.php-version == '8.2' && github.event_name == 'pull_request' }}
        run:  echo 'Artifact URL is ${{ steps.artifact-upload-step.outputs.artifact-url }}'

      - name: Generate code coverage markdown report
        if: ${{ matrix.php-version == '8.2' && github.event_name == 'pull_request' }}
        run: |
          ./tools/php-diff-test markdown-report --input-file "./tests/_reports/branch/branch.cov" --output-file code-coverage.md
        
      - name: Add code coverage comment to PR
        uses: mshick/add-pr-comment@v2
        if: ${{ matrix.php-version == '8.2' && github.event_name == 'pull_request' }}
        with:
          message-path: |
            code-coverage.md

      - name: Commit coverage badge
        if: ${{ github.ref == 'refs/heads/main' && matrix.php-version == '8.2' }} # only commit on main, on the PHP version we're using in production.
        uses: stefanzweifel/git-auto-commit-action@v5
        with:
          commit_user_name: "Team"
          commit_user_email: "email@team.com"
          file_pattern: '.github/coverage.svg'
          commit_message: "🤖 Update coverage badge"
          commit_author: Team <email@team.com>
          skip_dirty_check: false
          skip_fetch: false
        env:
          GITHUB_TOKEN: ${{ secrets.DEPLOY_KEY }}

TODO

• I think the diff doesn't track unstaged/uncommitted files which could have code coverage
• Also run tests changed in the diff / run all tests changed since the code coverage was generated (i.e. Tests written after the code coverage report are not included in the filter)
• Figure how best merge/increment coverage reports – i.e. once php-diff-test coverage has been run on the full coverage report, add to it when new tests are written
• Allow specifying a hash to diff with – i.e. make pull requests run faster
• sebastianbergmann/php-code-coverage#571 – code coverage annotations make this tool less thorough
• Tidy up the code – I'm not sure is the diff report's lines the current lines or the before lines... use both for best effect
• Tests!
• Should this be implemented as a PHPUnit extension?

See Also

• https://github.com/robiningelbrecht/phpunit-coverage-tools
• https://docs.phpunit.de/en/10.5/extending-phpunit.html
• https://localheinz.com/articles/2023/02/14/extending-phpunit-with-its-new-event-system/