Add backend unit/integration tests, Playwright e2e tests, README, cookie Secure fix

backend/tests/integration/setup/testDb.ts

@@ -0,0 +1,27 @@
+import { Pool } from 'pg';
+import fs from 'fs';
+import path from 'path';
+
+export const testPool = new Pool({
+  host: process.env.TEST_PGHOST || 'localhost',
+  port: parseInt(process.env.TEST_PGPORT || '55432', 10),
+  user: process.env.TEST_PGUSER || 'redefined_test',
+  password: process.env.TEST_PGPASSWORD || 'redefined_test',
+  database: process.env.TEST_PGDATABASE || 'redefined_test'
+});
+
+export async function migrate(): Promise<void> {
+  const sql = fs.readFileSync(path.join(__dirname, '..', '..', '..', 'init.sql'), 'utf-8');
+  await testPool.query(sql);
+}
+
+export async function resetDb(): Promise<void> {
+  await testPool.query(`
+    TRUNCATE TABLE orders, customer_tokens, customer_sessions, customers, item_images, items
+    RESTART IDENTITY CASCADE
+  `);
+}
+
+export async function closeDb(): Promise<void> {
+  await testPool.end();
+}