Module 5 · Testing, security and shipping Lesson 13 of 15
Tests for the API you just built
A few API tests turn "it works when I click it" into something a machine checks on every change. Test the routes, the happy path and the failures.
The concept
Test against a separate test database the suite creates and drops, so a run never touches the data you are using to develop.
Test status codes and the body together; an endpoint that returns 200 with an error message inside is a bug the front end will trip over.
import request from 'supertest';
import app from '../app.js';
test('POST /api/jobs creates a job', async () => {
const res = await request(app)
.post('/api/jobs')
.send({ title: 'Data Analyst', city: 'Pune' });
expect(res.status).toBe(201);
expect(res.body).toHaveProperty('id');
});
test('POST /api/jobs rejects a missing title', async () => {
const res = await request(app).post('/api/jobs').send({ city: 'Pune' });
expect(res.status).toBe(400);
});Worked example
A test that posts a bad payload and asserts 400 guards the validation you wrote and prevents a later "small change" from removing it.
Your practice task
Write three tests for your API: a successful request, a missing field, and an unauthorised request.
Do this before moving on. Reading a solution teaches the shape of it; typing it teaches you.
Key takeaway
Test against a separate test database the suite creates and drops, so a run never touches the data you are using to develop.
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