Jest test are run before DB is ready

问题

I am using Jest to test my express API with SQLite database, but the following problem appeared - test are run before DB is ready and tables are created.

I connect to DB with following code:

const connectToDatabase = () => {
  let db;
  if (process.env.NODE_ENV === 'development' || process.env.NODE_ENV === 'production') {
    db = new sqlite3.Database('task_list');
  } else if (process.env.NODE_ENV === 'test') {
    db = new sqlite3.Database(':memory:');
  } else {
    throw new Error('Environment is not defined!');
  }
  db.pRun = promisify(db.run, db);
  db.pGet = promisify(db.get, db);
  db.pAll = promisify(db.all, db);
  db.pClose = promisify(db.close, db);
  return db;
};

and then check tables existence (and create them) with

const prepareTables = async (db) => {
  // check existence of 'users' table
  try {
    const usersTable = await db.pGet("SELECT name FROM sqlite_master WHERE type='table' AND name='users'");
    if (!usersTable) {
      // create table
      db.pRun(`
        CREATE TABLE users (
          id TEXT,
          username TEXT,
          email TEXT,
          password TEXT
        )
      `);
    }
  } catch (err) {
    console.log('error', err); // eslint-disable-line no-console
  }
}

and then export DB for using in API methods. My method is:

const createUser = async (req, res) => {
  // create user
  try {
    const newUser = {
      id: uuid.v4(),
      username: req.body.username,
      email: req.body.email,
      password: bcrypt.hashSync(req.body.password)
    }
    await db.pRun(`
      INSERT INTO USERS (id, username, email, password)
      VALUES (
        "${newUser.id}",
        "${newUser.username}",
        "${newUser.email}",
        "${newUser.password}"
      )
    `);
    const response = await db.pGet(`SELECT * FROM users WHERE id='${newUser.id}'`);
    delete response.password;
    res.status(200).send(response);
  } catch (err) {
    console.log(err); // eslint-disable-line no-console
    res.status(500).send("Unlucky, database error.");
  }
}

And it works fine when server is started and I manually call it via Postman. But my test:

it('should create new user', async (done) => {
    const res = await request(app)
      .post('/api/users/')
      .send({
        username: 'username',
        password: 'password',
        email: 'test@test.com'
      });
    expect(res.statusCode).toEqual(200);
    done();
  })

Doesn't work complaining about tables aren't created. I console logged db and it's true. Looks like API is being called before server successfully started and tables are formatted. I use in-memory DB, so it needs to be formatted every time. Any suggestions how to achieve desired behavior? Thanks.

回答1:

I should read Jest docs carefully, there is an option right for my case. I added file with DB initialization to "setupFiles" array in my package.json and it works fine.

来源：https://stackoverflow.com/questions/46534802/jest-test-are-run-before-db-is-ready

标签

node.js

sqlite

express

supertest