test(federation): integration tests for federated tier gateway boot (FED-M1-07) (#476)

apps/gateway/src/__tests__/integration/federated-boot.pg-unreachable.integration.test.ts

@@ -0,0 +1,64 @@
+/**
+ * Test B — Gateway boot refuses (fail-fast) when PG is unreachable.
+ *
+ * Prereq: docker compose -f docker-compose.federated.yml --profile federated up -d
+ *         (Valkey must be running; only PG is intentionally misconfigured.)
+ * Run:    FEDERATED_INTEGRATION=1 pnpm --filter @mosaicstack/gateway test src/__tests__/integration/federated-boot.pg-unreachable.integration.test.ts
+ *
+ * Skipped when FEDERATED_INTEGRATION !== '1'.
+ */
+
+import net from 'node:net';
+import { beforeAll, describe, expect, it } from 'vitest';
+import { TierDetectionError, detectAndAssertTier } from '@mosaicstack/storage';
+
+const run = process.env['FEDERATED_INTEGRATION'] === '1';
+
+const VALKEY_URL = 'redis://localhost:6380';
+
+/**
+ * Reserves a guaranteed-closed port at runtime by binding to an ephemeral OS
+ * port (port 0) and immediately releasing it. The OS will not reassign the
+ * port during the TIME_WAIT window, so it remains closed for the duration of
+ * this test.
+ */
+async function reserveClosedPort(): Promise<number> {
+  return new Promise((resolve, reject) => {
+    const server = net.createServer();
+    server.listen(0, '127.0.0.1', () => {
+      const addr = server.address();
+      if (typeof addr !== 'object' || !addr) return reject(new Error('no addr'));
+      const port = addr.port;
+      server.close(() => resolve(port));
+    });
+    server.on('error', reject);
+  });
+}
+
+describe.skipIf(!run)('federated boot — PG unreachable', () => {
+  let badPgUrl: string;
+
+  beforeAll(async () => {
+    const closedPort = await reserveClosedPort();
+    badPgUrl = `postgresql://mosaic:mosaic@localhost:${closedPort}/mosaic`;
+  });
+
+  it('detectAndAssertTier throws TierDetectionError with service: postgres when PG is down', async () => {
+    const brokenConfig = {
+      tier: 'federated' as const,
+      storage: {
+        type: 'postgres' as const,
+        url: badPgUrl,
+        enableVector: true,
+      },
+      queue: {
+        type: 'bullmq',
+        url: VALKEY_URL,
+      },
+    };
+
+    await expect(detectAndAssertTier(brokenConfig)).rejects.toSatisfy(
+      (err: unknown) => err instanceof TierDetectionError && err.service === 'postgres',
+    );
+  }, 10_000);
+});