fix(frontend): report coverage from the browser-mode tests

.github/workflows/build.yml

@@ -161,7 +161,19 @@ jobs:
       - name: Install Playwright Chromium
         run: yarn --cwd frontend playwright install ${{ matrix.os == 'ubuntu-latest' && '--with-deps' || '' }} chromium
       - name: Run frontend browser-mode tests
-        run: yarn --cwd frontend ng run gui:test-browser
+        run: yarn --cwd frontend ng run gui:test-browser --coverage --coverage-reporters=lcovonly
+      - name: Upload frontend browser-mode coverage to Codecov
+        # These tests already exercise code the jsdom run cannot reach (Monaco, real
+        # pointer input); without this upload those lines are reported as uncovered.
+        # vitest.browser.config.ts writes to coverage-browser/ so this does not collide
+        # with the jsdom run's coverage/gui/lcov.info.
+        if: matrix.os == 'ubuntu-latest' && always()
+        uses: codecov/codecov-action@fb8b3582c8e4def4969c97caa2f19720cb33a72f # v7.0.0
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: ./frontend/coverage-browser/**/lcov.info
+          flags: frontend
+          fail_ci_if_error: false
       - name: Upload frontend browser-mode test results to Codecov
         # vitest.browser.config.ts emits junit-browser.xml (distinct from
         # the unit-test report). Same `frontend` flag — Codecov merges

frontend/.gitignore

@@ -10,6 +10,7 @@
 
 # test coverage
 /coverage
+/coverage-browser
 
 # vitest browser-mode snapshot baselines
 **/__screenshots__/

frontend/vitest.browser.config.ts

@@ -47,15 +47,27 @@ export default defineConfig({
   // `require()` calls inside the CJS package crash on first import.
   // Explicit-include forces esbuild to pre-bundle it (alongside its
   // `base64-js` + `ieee754` transitive deps) into a browser-runnable ESM.
+  //
+  // `@vitest/coverage-v8/browser` is loaded dynamically by the coverage provider once
+  // `--coverage` is passed, and it is not in the import graph either, so it needs the same
+  // hint. Without it the run fails with "Failed to fetch dynamically imported module:
+  // /@id/@vitest/coverage-v8/browser" and no coverage is produced -- the tests still pass,
+  // which is why the gap went unnoticed.
   optimizeDeps: {
-    include: ["buffer"],
+    include: ["buffer", "@vitest/coverage-v8/browser"],
   },
   test: {
     // Emit a JUnit-XML report alongside the default console reporter so
     // Codecov Test Analytics can ingest browser-mode failures and detect
     // flakies on main. Written to a distinct filename so the upload step
     // can disambiguate it from the unit-test report.
     reporters: ["default", ["junit", { outputFile: "junit-browser.xml" }]],
+    // Written to its own directory so it does not overwrite the jsdom run's
+    // coverage/gui/lcov.info. Codecov merges multiple uploads under one flag, so both
+    // records count and the lines these tests already exercise stop reading as uncovered.
+    coverage: {
+      reportsDirectory: "coverage-browser",
+    },
     globals: true,
     // browser-buffer-polyfill must run FIRST: it puts Buffer/process on
     // globalThis before any test module loads, which is required for