feat(ci): split test job into unit/integration/e2e matrix + Codecov flags (#3559)

* feat(ci): split test job into unit/integration/e2e matrix + Codecov flags

Axis B parallelization: the monolithic test job is split into a 3-way
matrix (unit / integration / e2e) so each category runs on its own
runner concurrently. Per-job heap drops 6144 → 4096 MB since each job
handles ~half the suites. e2e runs as a pure pass/fail gate without
coverage upload (product-flow paths, not coverage drivers). Unit and
integration each upload a Codecov flag; Codecov merges them server-side
so the combined % reflects lines covered by at least one job.

- package.json: add test:unit:coverage + test:integration:coverage;
  legacy test:coverage kept as local dev convenience alias
- jest.config.js: remove coverageThreshold — gating moves to Codecov
  status checks (per-job thresholds fail since each covers only a slice)
- codecov.yml: add unit/integration flags, after_n_builds: 2, comment
  layout with flags panel; preserve existing project/patch auto targets
- CI.yml: matrix strategy with fail-fast: false, lint once on unit job,
  conditional coverage upload skipped for e2e
- README: document the new per-category scripts and CI matrix

* ci: pin codecov/codecov-action to full SHA (v5.5.4)

* fix(ci): guard coverage upload with !cancelled() + token env check

- !cancelled() prevents Codecov from hanging on after_n_builds: 2 when
  a test job fails and skips its upload step
- env.CODECOV_TOKEN != '' restores fork-PR guard from original CI; on
  forks secrets.* are empty so the step would fail without this guard

Author: PierreBrisorgueil

.github/workflows/CI.yml

@@ -20,6 +20,10 @@ concurrency:
 
 jobs:
   test:
+    strategy:
+      fail-fast: false
+      matrix:
+        suite: [unit, integration, e2e]
     runs-on: ${{ vars.RUNNER || 'ubuntu-latest' }}
     timeout-minutes: 30
 
@@ -49,16 +53,29 @@ jobs:
 
       - run: npm ci
 
-      - run: npm run lint
-
-      - run: npm run test:coverage
-
-      - uses: codecov/codecov-action@v5
-        if: env.CODECOV_TOKEN != ''
+      - name: Lint (once on the unit job)
+        if: matrix.suite == 'unit'
+        run: npm run lint
+
+      - name: Run tests
+        run: |
+          case "${{ matrix.suite }}" in
+            unit|integration)
+              npm run test:${{ matrix.suite }}:coverage
+              ;;
+            e2e)
+              npm run test:e2e
+              ;;
+          esac
+
+      - name: Upload coverage
+        if: "!cancelled() && matrix.suite != 'e2e' && env.CODECOV_TOKEN != ''"
+        uses: codecov/codecov-action@75cd11691c0faa626561e295848008c8a7dddffe  # v5.5.4
         env:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
+          flags: ${{ matrix.suite }}
           slug: ${{ github.repository }}
 
   parallel-smoke:

README.md

@@ -83,14 +83,18 @@ npm run prod
 ### Testing
 
 ```bash
-npm test                       # Run all tests (one-shot)
-npm run test:unit              # Run unit tests once (alias of npm test)
-npm run test:watch             # Run tests in watch mode
-npm run test:coverage          # Generate coverage report
-npm run test:parallel-smoke    # Regression gate for per-pid test DB isolation (#3515)
+npm test                            # Run unit tests (one-shot)
+npm run test:unit                   # Run unit tests once (alias of npm test)
+npm run test:integration            # Run integration tests once
+npm run test:e2e                    # Run e2e tests once (pass/fail gate, no coverage)
+npm run test:watch                  # Run tests in watch mode
+npm run test:unit:coverage          # Unit tests + coverage report (CI: unit matrix job)
+npm run test:integration:coverage   # Integration tests + coverage report (CI: integration matrix job)
+npm run test:coverage               # Legacy alias: all suites + coverage (local dev convenience)
+npm run test:parallel-smoke         # Regression gate for per-pid test DB isolation (#3515)
 ```
 
-Tests are organized per module in `modules/*/tests/`. The `test:parallel-smoke` script spawns N concurrent jest children against the same mongod and asserts none of them trample each other — gates against accidental regression of the per-pid `NodeTest_${pid}` default in `config/defaults/test.config.js`. Off the critical path in CI (own job), so it never blocks merges.
+Tests are organized per module in `modules/*/tests/`. In CI the test job runs as a 3-way matrix (`unit` / `integration` / `e2e`) in parallel: `unit` and `integration` each upload a Codecov flag, and Codecov merges them server-side to compute combined coverage. e2e tests run as a pure pass/fail gate without coverage upload — they verify product-critical flows, not coverage. The `test:parallel-smoke` script spawns N concurrent jest children against the same mongod and asserts none of them trample each other — gates against accidental regression of the per-pid `NodeTest_${pid}` default in `config/defaults/test.config.js`. Off the critical path in CI (own job), so it never blocks merges.
 
 ### Code Quality
 

codecov.yml

@@ -3,6 +3,36 @@ coverage:
     project:
       default:
         target: auto
+        threshold: 0.5%
+        flags:
+          - unit
+          - integration
     patch:
       default:
-        target: 80%
+        target: auto
+        threshold: 0%
+        flags:
+          - unit
+          - integration
+
+flags:
+  unit:
+    paths:
+      - lib
+      - modules
+      - config
+  integration:
+    paths:
+      - lib
+      - modules
+      - config
+
+comment:
+  layout: "header, diff, flags, components, footer"
+  behavior: default
+  require_changes: false
+
+# Wait for both flags to upload before posting status
+codecov:
+  notify:
+    after_n_builds: 2

jest.config.js

@@ -64,15 +64,9 @@ export default {
   // A list of reporter names that Jest uses when writing coverage reports
   coverageReporters: ['json', 'lcov', 'clover', 'text'],
 
-  // An object that configures minimum threshold enforcement for coverage results
-  coverageThreshold: {
-    global: {
-      statements: 80,
-      branches: 65,
-      functions: 80,
-      lines: 80,
-    },
-  },
+  // coverageThreshold removed — coverage gating moved to Codecov status checks
+  // (unit + integration flags merged server-side; per-job thresholds would fail
+  //  since each job covers only its slice of source paths)
 
   // Make calling deprecated APIs throw helpful error messages
   // errorOnDeprecated: false,

package.json

@@ -35,6 +35,8 @@
     "test:e2e": "cross-env NODE_ENV=test NODE_OPTIONS=--experimental-vm-modules jest --runInBand --testPathPatterns='e2e'",
     "test:watch": "cross-env NODE_ENV=test NODE_OPTIONS=--experimental-vm-modules jest --watchAll",
     "test:coverage": "cross-env NODE_ENV=test NODE_OPTIONS=\"--experimental-vm-modules --max-old-space-size=6144 --expose-gc\" jest --coverage --maxWorkers=2",
+    "test:unit:coverage": "cross-env NODE_ENV=test NODE_OPTIONS=\"--experimental-vm-modules --max-old-space-size=4096 --expose-gc\" jest --coverage --maxWorkers=2 --testPathPatterns='unit'",
+    "test:integration:coverage": "cross-env NODE_ENV=test NODE_OPTIONS=\"--experimental-vm-modules --max-old-space-size=4096 --expose-gc\" jest --coverage --maxWorkers=2 --testPathPatterns='integration'",
     "test:parallel-smoke": "cross-env NODE_ENV=test node scripts/parallel-integration.smoke.js",
     "lint": "eslint ./modules ./lib ./config ./scripts",
     "seed:dev": "cross-env NODE_ENV=development node scripts/seed.js seed",