node-docker-redis-test

Example of how to test redis in a NodeJS TypeScript project

The StorageService is a simple redis consuming client using ioredis.

This is tested using StorageService.test.ts which, rather than mocking ioredis instead stands up a redis container.

For the redis container, the docker-test-containers module in the test directory contains a DockerTestContainer base class, which can be used to build any docker container. This uses dockerode under the hood.

The RedisDocker class is a subclass of DockerTestContainer which supplies the base implementation with the details it needs to make a redis container suitable for this application.

The test code is pretty quick to execute.

The boilerplate for set up of the redis cluster:

const redisDocker = new RedisDocker();
let storageService: StorageService;

beforeAll(async () => {
  await redisDocker.createContainer();
  storageService = new StorageService(redisDocker.getHost(), redisDocker.getPort());
});

afterAll(async () => {
  await redisDocker.stop();
  await storageService.close();
});

beforeEach(async () => {
  // this purges all records, giving us a clean container, which is cheaper than starting a new one each time
  await storageService.flushall();
});

Warning: dockerode's docker pull doesn't quite seem to work, and you cannot just create a container image by providing its name - it needs to have been pulled first. I've solved this in other projects by simply adding docker pull redis:6.2.6 or similar to either the build script, or to the test script within package.json.