server and db connection once before all test files jest - node.js

Question

I have multiple test files in my project. Each test file has almost similar beforeAll and afterAll functions which opens server and db connections and terminate them in the afterAll function.
I was getting error for server connection which said the port is already in use and I was able to handle that by not specifying a port number in test environment. However I'm unable to solve for db.
The lines below in .test.js file are common in all test files. The test itself is a dummy test. I need to have access to server in order to call the APIs there.
.test.js
const db = require('../service/pg');
const createServer = require('../service/server');
let server;
let sequelize;
beforeAll(async () => {
sequelize = await db.init();
server = await createServer();
await server.start();
});
afterAll(async () => {
await server.stop();
await sequelize.drop();
await sequelize.close();
});
describe('testing...', () => {
test('one + one = 2', async () => {
const options = {
method: 'POST',
url: '/math',
};
const res= await server.inject(options);
expect(1).toEqual(1);
});
server.js
if (process.env.NODE_ENV !== 'test') {
server = Hapi.server({
port: process.env.PORT || 5000,
routes: { cors: true },
});
}
db.js
const sequelize = require('./sequelize');
await sequelize.sync();
sequelize.js
const user_db = new Sequelize(
env.dbName,
env.user,
env.password,
{
host: env.host,
port: env.port,
dialect: 'postgres',
logging: false,
}
);
.... // add models
Ideal solution would be initializing server and DB only once for all test files. Some global setup stuff. But I'm unable to do that.
If I have like 2 test files, one test file works file but the other would give error like:
console.error
Connection to the database failed: UniqueConstraintError [SequelizeUniqueConstraintError]: Validation error

Answer 1

Instead of setting up your db in the beforeAll do it outside of the describe scope once and stop the servers afterwards.
const db = require('../service/pg');
const createServer = require('../service/server');
let server;
let sequelize;
(async () => {
sequelize = await db.init();
server = await createServer();
await server.start();
})();
describe('testing...', () => {
test('one + one = 2', async () => {
const options = {
method: 'POST',
url: '/math',
};
const res= await server.inject(options);
expect(1).toEqual(1);
});
});
(async () => {
await server.stop();
await sequelize.drop();
await sequelize.close();
})();
If I have like 2 test files, one test file works file but the other would give error like: console.error Connection to the database failed: UniqueConstraintError [SequelizeUniqueConstraintError]: Validation error
The reason for this is that jest runs tests in parallel and it could be that your second test starts before the first one has been finished and the afterAll has been called.