Automated Testing with Databases

Question

I'm fairly new to automated testing and was wondering how I should go about writing tests for the database. The project I'm working on right now is running PostgreSQL with Sequelize as the ORM on a Node.JS environment. If it matters, I'm also using Jest as the testing library right now.

Answer 1

In my app I use a config module to control configuration settings for different environments. When running tests the process.env.APP_ENV is set to test, and it will set the dialect to sqlite. Note that you will not have any data or data persistence, so you will need to populate it with all the data needed for your tests.

Include sqlite3

yarn add -D sqlite3

or

npm i -D sqlite3

Config

module.exports = {
  database: {
    name: 'dbname',
    user: 'user',
    password: 'password',
    host: 'host',
    // Use "sqlite" for "test", the connection settings above are ignored
    dialect: process.env.APP_ENV === 'test' ? 'sqlite' : 'mysql',
  },
};

Database/Sequelize

// get our config
const config = require('../config');

... // code

const instance = new Sequelize(
    config.database.name,
    config.database.user,
    config.database.password,
    {
      host: config.database.host,
      // set the dialect, will be "sqlite" for "test"
      dialect: config.database.dialect,
    }
);

Test Class (Mocha)

const TestUtils = require('./lib/test-utils');

describe('Some Tests', () => {
  let app = null;

  // run before the tests start
  before((done) => {
    // Mock up our services
    TestUtils.mock();

    // these are instantiated after the mocking
    app = require('../server');

    // Populate redis data
    TestUtils.populateRedis(() => {
      // Populate db data
      TestUtils.syncAndPopulateDatabase('test-data', () => {
        done();
      });
    });
  });

  // run code after tests have completed
  after(() => {
    TestUtils.unMock();
  });

  describe('/my/route', () => {
    it('should do something', (done) => {
      return done();
    });
  });
});

Run Tests

APP_ENV=test ./node_modules/.bin/mocha

You could use ENV variables in other ways to set the dialect and connection parameters as well - the above is just an example based on what we have done with a lot of supporting code.