Use LCOV combined coverage

.github/workflows/ci.yml

@@ -40,3 +40,25 @@ jobs:
       - run: npm test
       - run: npm run test:ts
         if: (matrix.node-version != '12.x' && matrix.node-version != '14.x' && matrix.node-version != '16.10.0')
+      - name: Archive code coverage results
+        if: success()
+        uses: actions/upload-artifact@v3
+        with:
+          name: coverage_${{ matrix.os }}_${{ matrix.node-version}}
+          if-no-files-found: ignore
+          path: coverage/lcov.info
+
+  coverage:
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Download reports' artifacts
+        uses: actions/download-artifact@v3
+        with:
+          path: downloaded_artifacts
+      - name: Install lcov
+        run: sudo apt install -y lcov
+      - name: Combine all coverage data
+        run: find . -type f -name '*.info' -printf '-a\0%f\0' | xargs -J % -0 -- lcov % -o all_lcov.info
+      - name: Report
+        run: lcov --summary all_lcov.info --fail-under-lines 90

package.json

@@ -4,8 +4,8 @@
   "description": "Intercept imports in Node.js",
   "main": "index.js",
   "scripts": {
-    "test": "c8 --check-coverage --lines 85 imhotap --runner 'node test/runtest' --files test/{hook,low-level,other,get-esm-exports}/*",
-    "test:ts": "c8 imhotap --runner 'node test/runtest' --files test/typescript/*.test.mts",
+    "test": "c8 --reporter lcov --check-coverage --lines 85 imhotap --runner 'node test/runtest' --files test/{hook,low-level,other,get-esm-exports}/*",
+    "test:ts": "c8 --reporter lcov imhotap --runner 'node test/runtest' --files test/typescript/*.test.mts",
     "coverage": "c8 --reporter html imhotap --runner 'node test/runtest' --files test/{hook,low-level,other,get-esm-exports}/* && echo '\nNow open coverage/index.html\n'"
   },
   "repository": {