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Posted on Mar 28

Write e2e tests for NestJS with testcontainers

So I was really annoyed last time I was trying to mock and have some tests for my NestJS app. So I decided to try testcontainers once more.

Last time I was trying to mock BullMQ and it was giving me a hard time, and this time around I managed to get it working.

Stick around and see how I did it.

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Code

So basically I really do not wanna spy one anything or mock for that matter. But rather I am only interested in knowing that my queue received a message and did its job, e.g. called an external API.

Actually here I am not gonna test that but if you need to verify that the external API was called I think you can simply have a Wiremock Testcontainer and check it was called.

I will not cover that case here, at least not now. But what I am interested to show you here is how the e2e test will look like:

import { Test, TestingModule } from '@nestjs/testing'; import { INestApplication } from '@nestjs/common'; import { RedisContainer } from '@testcontainers/redis'; import * as request from 'supertest'; import { App } from 'supertest/types'; import { AppModule } from './../src/app.module'; describe('AppController (e2e)', () => { let app: INestApplication<App>; beforeAll(async () => { const container = await new RedisContainer().start(); process.env.SERVICE_NAME = 'test'; process.env.REDIS_URI = container.getHostname(); process.env.REDIS_PORT = container.getPort().toString(); const moduleFixture: TestingModule = await Test.createTestingModule({ imports: [AppModule], }).compile(); app = moduleFixture.createNestApplication(); await app.init(); }); it('/ (GET)', async () => { const res = await request(app.getHttpServer()).get('/'); expect(res.status).toBe(200); expect(res.text).toBe('Hello World!'); }); });

NOTE

Here I was not trying to use ConfigService, so I just hacked in my way into the process.env. But feel free to check my repo for a more mature way of dealing with env variables.