ci: add coverage trend monitoring

.github/workflows/coverage-report.yml

@@ -0,0 +1,55 @@
+name: Coverage Report
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  report:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Generate coverage
+        run: |
+          npm run test:unit -- --coverage
+          node scripts/coverage-trend.js > coverage-metrics.json
+
+      - name: Upload metrics
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-metrics
+          path: coverage-metrics.json
+
+      - name: Comment coverage on PR
+        if: github.event_name == 'pull_request'
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const fs = require('fs');
+            const metrics = JSON.parse(fs.readFileSync('coverage-metrics.json', 'utf8'));
+            
+            const comment = `## Coverage Report
+            
+            - Statements: ${metrics.statements}%
+            - Branches: ${metrics.branches}%
+            - Functions: ${metrics.functions}%
+            - Lines: ${metrics.lines}%
+            
+            Generated at: ${metrics.timestamp}`;
+            
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: comment
+            });
+          github-token: ${{ secrets.GITHUB_TOKEN }}

scripts/coverage-trend.js

@@ -0,0 +1,26 @@
+const fs = require('fs');
+const path = require('path');
+
+const coverageFilePath = path.join(__dirname, '..', 'coverage', 'coverage-final.json');
+
+try {
+  if (!fs.existsSync(coverageFilePath)) {
+    console.error('Coverage file not found:', coverageFilePath);
+    process.exit(1);
+  }
+
+  const coverage = JSON.parse(fs.readFileSync(coverageFilePath, 'utf8'));
+
+  const metrics = {
+    statements: coverage.total.statements.pct,
+    branches: coverage.total.branches.pct,
+    functions: coverage.total.functions.pct,
+    lines: coverage.total.lines.pct,
+    timestamp: new Date().toISOString(),
+  };
+
+  console.log(JSON.stringify(metrics, null, 2));
+} catch (error) {
+  console.error('Error reading coverage:', error.message);
+  process.exit(1);
+}