test-coverage.yml

name: Test Coverage

on:
  pull_request:
    branches: [main]
    paths-ignore:
      - '**/*.md'
      - '.github/workflows/release.yml'
  push:
    branches: [main]

permissions:
  contents: read
  pull-requests: write
  checks: write

jobs:
  coverage:
    name: Test Coverage Report
    runs-on: ubuntu-latest
    timeout-minutes: 15

    steps:
      - name: Checkout repository
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v4
        with:
          fetch-depth: 0

      - name: Setup Node.js
        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
        with:
          node-version: '20'
          cache: 'npm'

      - name: Install dependencies
        run: npm ci

      - name: Build project
        run: npm run build

      - name: Run tests with coverage (PR branch)
        run: npm run test:coverage

      - name: Save PR coverage
        run: cp coverage/coverage-summary.json /tmp/pr-coverage-summary.json

      - name: Get base branch coverage (PR only)
        if: github.event_name == 'pull_request'
        id: base_coverage
        run: |
          # Save the current commit
          PR_COMMIT=$(git rev-parse HEAD)

          # Checkout base branch
          git checkout ${{ github.event.pull_request.base.sha }}

          # Install dependencies and build for base branch
          npm ci
          npm run build

          # Run coverage on base branch
          npm run test:coverage || true

          # Save base coverage
          if [ -f coverage/coverage-summary.json ]; then
            cp coverage/coverage-summary.json /tmp/base-coverage-summary.json
            echo "base_coverage_exists=true" >> $GITHUB_OUTPUT
          else
            echo "base_coverage_exists=false" >> $GITHUB_OUTPUT
          fi

          # Checkout back to PR commit
          git checkout $PR_COMMIT

          # Reinstall PR dependencies
          npm ci

      - name: Compare coverage (PR only)
        if: github.event_name == 'pull_request' && steps.base_coverage.outputs.base_coverage_exists == 'true'
        id: compare
        run: |
          npx tsx scripts/ci/compare-coverage.ts \
            /tmp/pr-coverage-summary.json \
            /tmp/base-coverage-summary.json
        continue-on-error: true

      - name: Generate coverage summary (push to main)
        if: github.event_name == 'push'
        id: coverage
        run: |
          # Read the coverage summary
          COVERAGE_JSON=$(cat coverage/coverage-summary.json)

          # Extract metrics using jq
          LINES_PCT=$(echo "$COVERAGE_JSON" | jq -r '.total.lines.pct')
          STATEMENTS_PCT=$(echo "$COVERAGE_JSON" | jq -r '.total.statements.pct')
          FUNCTIONS_PCT=$(echo "$COVERAGE_JSON" | jq -r '.total.functions.pct')
          BRANCHES_PCT=$(echo "$COVERAGE_JSON" | jq -r '.total.branches.pct')

          LINES_COVERED=$(echo "$COVERAGE_JSON" | jq -r '.total.lines.covered')
          LINES_TOTAL=$(echo "$COVERAGE_JSON" | jq -r '.total.lines.total')
          STATEMENTS_COVERED=$(echo "$COVERAGE_JSON" | jq -r '.total.statements.covered')
          STATEMENTS_TOTAL=$(echo "$COVERAGE_JSON" | jq -r '.total.statements.total')
          FUNCTIONS_COVERED=$(echo "$COVERAGE_JSON" | jq -r '.total.functions.covered')
          FUNCTIONS_TOTAL=$(echo "$COVERAGE_JSON" | jq -r '.total.functions.total')
          BRANCHES_COVERED=$(echo "$COVERAGE_JSON" | jq -r '.total.branches.covered')
          BRANCHES_TOTAL=$(echo "$COVERAGE_JSON" | jq -r '.total.branches.total')

          # Create summary for GitHub Actions Summary
          echo "## Test Coverage Report" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY
          echo "| Metric | Coverage | Covered/Total |" >> $GITHUB_STEP_SUMMARY
          echo "|--------|----------|---------------|" >> $GITHUB_STEP_SUMMARY
          echo "| **Lines** | ${LINES_PCT}% | ${LINES_COVERED}/${LINES_TOTAL} |" >> $GITHUB_STEP_SUMMARY
          echo "| **Statements** | ${STATEMENTS_PCT}% | ${STATEMENTS_COVERED}/${STATEMENTS_TOTAL} |" >> $GITHUB_STEP_SUMMARY
          echo "| **Functions** | ${FUNCTIONS_PCT}% | ${FUNCTIONS_COVERED}/${FUNCTIONS_TOTAL} |" >> $GITHUB_STEP_SUMMARY
          echo "| **Branches** | ${BRANCHES_PCT}% | ${BRANCHES_COVERED}/${BRANCHES_TOTAL} |" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY

          # Also save individual metrics as outputs
          echo "lines_pct=${LINES_PCT}" >> $GITHUB_OUTPUT
          echo "statements_pct=${STATEMENTS_PCT}" >> $GITHUB_OUTPUT
          echo "functions_pct=${FUNCTIONS_PCT}" >> $GITHUB_OUTPUT
          echo "branches_pct=${BRANCHES_PCT}" >> $GITHUB_OUTPUT

      - name: Comment PR with coverage comparison
        if: github.event_name == 'pull_request'
        continue-on-error: true
        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v7
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const fs = require('fs');

            // Try to read the coverage report from compare step
            let commentBody = process.env.COVERAGE_REPORT;

            // If no comparison report, generate a simple report
            if (!commentBody) {
              const prCoverage = JSON.parse(fs.readFileSync('/tmp/pr-coverage-summary.json', 'utf8'));
              const total = prCoverage.total;

              commentBody = `## 📊 Test Coverage Report

            | Metric | Coverage |
            |--------|----------|
            | Lines | ${total.lines.pct.toFixed(2)}% |
            | Statements | ${total.statements.pct.toFixed(2)}% |
            | Functions | ${total.functions.pct.toFixed(2)}% |
            | Branches | ${total.branches.pct.toFixed(2)}% |

            > ℹ️ Base branch coverage not available for comparison.

            ---
            *Coverage report generated by \`npm run test:coverage\`*`;
            }

            // Find existing coverage comment
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
            });

            const botComment = comments.find(comment =>
              comment.user.type === 'Bot' &&
              (comment.body.includes('Test Coverage Report') || comment.body.includes('Coverage Check'))
            );

            if (botComment) {
              // Update existing comment
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: botComment.id,
                body: commentBody
              });
            } else {
              // Create new comment
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                body: commentBody
              });
            }

      - name: Upload coverage reports
        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
        with:
          name: coverage-report
          path: |
            coverage/
          retention-days: 30

      - name: Fail on coverage regression
        if: github.event_name == 'pull_request' && steps.compare.outcome == 'failure'
        run: |
          echo "❌ Coverage regression detected!"
          echo "This PR decreases overall test coverage. Please add tests to maintain coverage levels."
          echo ""
          echo "See the PR comment above for detailed coverage comparison."
          exit 1