From 1286cd1eae23298d8c4ae5a5bc6b984070ce02f4 Mon Sep 17 00:00:00 2001
From: arsam <me@asabbagh.com>
Date: Fri, 18 Sep 2026 23:09:49 +0330
Subject: [PATCH] Import tests: backend/tests/integration/resilience

Import the existing local project snapshot. This commit organizes existing files; it does not represent newly developed functionality.
---
 backend/tests/integration/resilience.test.ts | 152 +++++++++++++++++++
 1 file changed, 152 insertions(+)
 create mode 100644 backend/tests/integration/resilience.test.ts

diff --git a/backend/tests/integration/resilience.test.ts b/backend/tests/integration/resilience.test.ts
new file mode 100644
index 0000000..1970999
--- /dev/null
+++ b/backend/tests/integration/resilience.test.ts
@@ -0,0 +1,152 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { execSync } from 'child_process';
+import Redis from 'ioredis';
+import { buildApp } from '../../src/app.js';
+
+describe('System Resilience & Database Connections', () => {
+  let app: ReturnType<typeof buildApp>;
+
+  beforeAll(async () => {
+    app = buildApp();
+    await app.ready();
+  });
+
+  afterAll(async () => {
+    await app.close();
+    // Safely ensure both services are running after tests finish
+    try {
+      execSync('systemctl start postgresql@18-main.service');
+    } catch {}
+    try {
+      execSync('systemctl start redis-server.service');
+    } catch {}
+  });
+
+  describe('PostgreSQL Connection Resilience', () => {
+    it('should report database: connected when PostgreSQL is up', async () => {
+      const res = await app.inject({
+        method: 'GET',
+        url: '/health',
+      });
+      expect(res.statusCode).toBe(200);
+      const body = JSON.parse(res.body);
+      expect(body.status).toBe('ok');
+      expect(body.database).toBe('connected');
+    });
+
+    it('should gracefully handle PostgreSQL going down', async () => {
+      // Stop PostgreSQL service
+      execSync('systemctl stop postgresql@18-main.service');
+
+      // Request health check (should return 500 error status and disconnected database)
+      const res = await app.inject({
+        method: 'GET',
+        url: '/health',
+      });
+      expect(res.statusCode).toBe(500);
+      const body = JSON.parse(res.body);
+      expect(body.status).toBe('error');
+      expect(body.database).toBe('disconnected');
+      expect(body.message).toBeDefined();
+    });
+
+    it('should automatically reconnect when PostgreSQL comes back up', async () => {
+      // Start PostgreSQL service
+      execSync('systemctl start postgresql@18-main.service');
+
+      // Wait a moment for PostgreSQL to start accepting connections
+      let retries = 5;
+      let connected = false;
+      while (retries > 0 && !connected) {
+        try {
+          const res = await app.inject({
+            method: 'GET',
+            url: '/health',
+          });
+          const body = JSON.parse(res.body);
+          if (res.statusCode === 200 && body.database === 'connected') {
+            connected = true;
+          }
+        } catch {}
+        if (!connected) {
+          await new Promise((resolve) => setTimeout(resolve, 1000));
+          retries--;
+        }
+      }
+
+      expect(connected).toBe(true);
+    });
+  });
+
+  describe('Redis Connection Resilience', () => {
+    let redis: Redis;
+
+    beforeAll(() => {
+      redis = new Redis('redis://127.0.0.1:6379', {
+        maxRetriesPerRequest: 1,
+        retryStrategy: () => 100, // retry quickly
+      });
+    });
+
+    afterAll(async () => {
+      await redis.quit();
+    });
+
+    it('should ping Redis successfully when it is up', async () => {
+      const pong = await redis.ping();
+      expect(pong).toBe('PONG');
+    });
+
+    it('should fail gracefully when Redis goes down', async () => {
+      // Stop Redis service
+      execSync('systemctl stop redis-server.service');
+
+      // Attempt ping - should fail / throw
+      await expect(redis.ping()).rejects.toThrow();
+    });
+
+    it('should automatically reconnect when Redis comes back up', async () => {
+      // Start Redis service
+      execSync('systemctl start redis-server.service');
+
+      // Wait and ping - should succeed again
+      let retries = 5;
+      let pong = '';
+      while (retries > 0 && pong !== 'PONG') {
+        try {
+          pong = await redis.ping();
+        } catch {}
+        if (pong !== 'PONG') {
+          await new Promise((resolve) => setTimeout(resolve, 1000));
+          retries--;
+        }
+      }
+      expect(pong).toBe('PONG');
+    });
+  });
+
+  describe('Global Error Handler & Config Validator', () => {
+    it('should categorize unhandled database/connection errors using the global error handler', async () => {
+      const testApp = buildApp();
+      // Register a test route that simulates an unhandled database error BEFORE ready()
+      testApp.get('/test-unhandled-db-error', async () => {
+        throw new Error('PrismaClientKnownRequestError: Can\'t reach database server');
+      });
+
+      await testApp.ready();
+
+      const res = await testApp.inject({
+        method: 'GET',
+        url: '/test-unhandled-db-error',
+      });
+
+      expect(res.statusCode).toBe(500);
+      const body = JSON.parse(res.body);
+      expect(body.error).toBeDefined();
+      expect(body.error.code).toBe('NETWORK_ERROR');
+      expect(body.error.message).toBe('An internal control plane error occurred.');
+
+      await testApp.close();
+    });
+  });
+});