fix(test): replace --runInBand with worker children + per-worker DB isolation (#3558)

* fix(test): replace --runInBand with worker children + per-worker DB isolation

Drops --runInBand from test:coverage so Jest spawns worker child processes,
making workerIdleMemoryLimit (#3550) effective and preventing the 4.9 GB OOM
seen in trawl_node (#1074). Adds JEST_WORKER_ID suffix to db.uri in
config/index.js so each worker targets an independent MongoDB database,
preventing data races when the CI DEVKIT_NODE_db_uri override is active.
globalSetup (no JEST_WORKER_ID) continues to operate on the unsuffixed URI.

* fix(test): use URL API for worker DB URI suffix (safer path manipulation)

Replaces the regex-based URI suffix with the URL API to correctly append
the worker suffix to the database name path segment. Handles URIs with no
explicit db name (defaults to 'test'), preserves query strings, and avoids
potential corruption of host/port components.

Author: PierreBrisorgueil

config/index.js

@@ -169,6 +169,28 @@ const initGlobalConfig = async () => {
   // Print a warning if config.domain is not set
   if (process.env.NODE_ENV !== 'test') configHelper.validateDomainIsSet(config);
   if (process.env.NODE_ENV !== 'test') configHelper.validateJwtSecret(config);
+
+  // Worker DB isolation: when running inside a jest worker (--maxWorkers > 1, no --runInBand),
+  // suffix db.uri with JEST_WORKER_ID so each worker hits an independent MongoDB database.
+  // Without this, the CI DEVKIT_NODE_db_uri override flattens all workers onto the same DB
+  // and causes data races. The main jest process (globalSetup) has no JEST_WORKER_ID so it
+  // operates on the unsuffixed URI, which is intentional (single drop+migrate).
+  if (process.env.NODE_ENV === 'test' && process.env.JEST_WORKER_ID) {
+    const workerId = process.env.JEST_WORKER_ID;
+    const uri = config.db?.uri ?? '';
+    const workerSuffix = `_w${workerId}`;
+    if (uri) {
+      // Use the URL API to safely append the worker suffix to the database name
+      // in the path segment, avoiding corruption of host/port or query string.
+      const parsed = new URL(uri);
+      const dbName = parsed.pathname.replace(/^\//, '') || 'test';
+      if (!dbName.endsWith(workerSuffix)) {
+        parsed.pathname = `/${dbName}${workerSuffix}`;
+        config.db.uri = parsed.toString();
+      }
+    }
+  }
+
   // Expose configuration utilities
   const conf = { ...config };
   conf.utils = {

package.json

@@ -34,7 +34,7 @@
     "test:integration": "cross-env NODE_ENV=test NODE_OPTIONS=--experimental-vm-modules jest --runInBand --testPathPatterns='integration'",
     "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 --runInBand",
+    "test:coverage": "cross-env NODE_ENV=test NODE_OPTIONS=\"--experimental-vm-modules --max-old-space-size=6144 --expose-gc\" jest --coverage --maxWorkers=2",
     "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",