What methods can be used to implement automated testing of API interfaces?

Automated API testing can be implemented in the following ways:

• Using specialized tools: Postman (with collections and JavaScript tests), SoapUI, Insomnia.
• Writing tests with programming languages and libraries: for example, JavaScript with Jest, Mocha, Chai, Supertest; Python with requests and pytest; Java with RestAssured.
• Integration with CI/CD: running tests automatically during project build.
• Testing various aspects of API: functional testing, response verification, status codes, response time, data schema validation (JSON Schema).

Example of a simple test in Node.js using Jest and Supertest:

const request = require('supertest');
const app = require('./app'); // your Express application

test('GET /api/users returns a list of users', async () => {
  const response = await request(app).get('/api/users');
  expect(response.statusCode).toBe(200);
  expect(Array.isArray(response.body)).toBe(true);
});