Test guidelines and tooling

tip

Test functionality not implementation

Implementation should change, tests should warn you when the functionality is broken.

Unit tests

• jest

foo.ts

export const bar = (value: number) => {
  return value+1;
}

foo.test.ts

import {bar} from './foo';

describe('foo module', () => {
  it('should work as expected', () => {
    expect(bar(0)).toBe(1);
  });
});

API tests

• supertest

myRouter.ts

import express from 'express';
import doc from './base/apiDoc';
import license from './base/licence';

const router = express.Router();

router.get('/foo', (req, res) => {
  res.status(200).send({value: 42})
});

export default router;

myRouter.test.ts

import request from 'supertest';
import router from './myRouter';
import { setupServer } from 'src/server';

const server = setupServer(app);

describe('My router', () => {
  it('should give the correct response', () => {
    return request(server).get('/foo')
      .expect(200)
      .then(res => {
        expect(res.body).toMatchObject({value: 42})
      })
  });
});

Persistency tests

• mongodb-memory-server

someRepository.ts

import mongoose from 'mongoose';
const schema = new mongoose.Schema({ name: 'string' });
export const User = mongoose.model('User', schema);

someRepository.test.ts

import initdb from 'src/db';
import mongoose from 'mongoose';
import { MongoMemoryServer } from 'mongodb-memory-server';
import { User } from './someRepository';

describe('db connection', () => {
  let dbServer: MongoMemoryServer;
  let connection: mongoose.Connection;
  
  beforeAll(async () => {
    dbServer = await MongoMemoryServer.create();
    connection = await initdb(dbServer.getUri());
  });

  afterAll(() => {
    connection.close();
    dbServer.stop();
  });

  it('should insert a doc into collection', async () => {
    const mockUser = { name: 'John' };
    const user = new User(mockUser);
    const { _id } = await user.save();

    const insertedUser = await User.findOne({ _id });
    expect(insertedUser).toMatchObject(mockUser);
  });
});

Test setup

See jest.config.ts for test settings.

Test configuration options are defined in config/test.yaml and can be optionally overriden in config/local-test.yaml.

Coverage and Qualimetry

Coverage report is generated when running tests and it's available under the coverage folder (see coverage/lcov-report/index.html for a comprehensive report)

TODO setup sonarqube