add test-cicd code

code/sample-nodejs-app/test/app.test.js

@@ -0,0 +1,19 @@
+const request = require('supertest');
+const app = require('../index');
+
+describe('GET /', () => {
+  it('should return 200 OK and a welcome message', async () => {
+    const res = await request(app).get('/');
+    expect(res.statusCode).toEqual(200);
+    expect(res.body).toHaveProperty('message');
+    expect(res.body.message).toContain('Hello World');
+  });
+});
+
+describe('GET /health', () => {
+  it('should return 200 OK', async () => {
+    const res = await request(app).get('/health');
+    expect(res.statusCode).toEqual(200);
+    expect(res.text).toEqual('OK');
+  });
+});