Have some issues when trying to use parametrize test in Playwright

Here is my code

const {test, expect} = require('@playwright/test')
const { generateRandomUser } = require('../helpers')

const firstUser = generateRandomUser();
const secondUser = generateRandomUser();
const users = [firstUser, secondUser];

// parametrized test
users.forEach(user => {
  console.log('USER', user);
  const { username, email, password } = user;
  test(`should register ${username}`, async ({ page }) => {
    await page.goto('https://conduit.mate.academy/user/register');

    await page.getByPlaceholder('Username').fill(username);
    await page.getByPlaceholder('Email').fill(email);
    await page.getByPlaceholder('Password').fill(password);
    await page.getByRole('button', { name: 'Sign up' }).click();

    await expect(page.locator(`a.nav-link[href='/profile/${username}']`)).toBeVisible();

    await page.pause();
  });
});

Here is the generateRandomUser function

const { faker } = require('@faker-js/faker');

exports.generateRandomUser = () => {
  const random = Math.random().toString().slice(2, 6);
  let username = faker.lorem.word() + '_' + random;
  username = username.toLowerCase()
  const email = username + '@gmail.com';
  const password = faker.internet.password();

  return {
    username,
    email,
    password
  }
}

So, basically I just want to have a good grasp of Playwright and just decided to try parametrize test, but when I run them I get this error

Internal error: unknown test(s) in worker:
chromium > exploring_playwright.spec.js > should register officiis_0247

2 failed
[chromium] › exploring_playwright.spec.js:12:3 › should register beatae_1183 ───────────────────
[chromium] › exploring_playwright.spec.js:12:3 › should register officiis_0247 ─────────────────

And moreover, when I use console.log() to see if the user was generated right I can see that in my console more than 2 outputs of users, which is strange, I guess this is the reason it fails but I have no idea how is it possible. I used this generateRandomUser() function for the previous tests and also for the Sign Up Page, like here and everything works fine.

const {test, expect} = require('@playwright/test')
const { generateRandomUser, registerNewUser } = require('../../helpers')

test.beforeEach(async ({page}) => {
  await page.goto('https://conduit.mate.academy/user/register');
})

test('should register a new user', async ({page}) => {
  const {username, email, password} = generateRandomUser();

  await page.getByPlaceholder('Username').fill(username);
  await page.getByPlaceholder('Email').fill(email);
  await page.getByPlaceholder('Password').fill(password);
  await page.getByRole('button', { name: 'Sign up' }).click();

  await expect(page.locator(`a.nav-link[href='/profile/${username}']`)).toBeVisible();
})

I tried to use resources like Youtube videos and documentation. Here is the references (photos) this one and this one

I asked ChatGPT, tried to add describe block, tried to use test.describe.parallel, but it didn't do much.

This option is also incorrect

for(let i = 0; i < 2; ++i) {
  const {username, email, password} = generateRandomUser();
  console.log(username, email, password)

  test(`should register ${username}`, async ({ page }) => {
    await page.goto('https://conduit.mate.academy/user/register');

    await page.getByPlaceholder('Username').fill(username);
    await page.getByPlaceholder('Email').fill(email);
    await page.getByPlaceholder('Password').fill(password);
    await page.getByRole('button', { name: 'Sign up' }).click();

    await expect(page.locator(`a.nav-link[href='/profile/${username}']`)).toBeVisible();

    await page.pause();
  });
}

I still see 6 users created instead of 2.

I beleive you might be running the tests on several workers which cause firstUser and secondUser to be generated for each worker. If you run the test with a single worker, the test will most likely run as expected:

// playwright.config
export default defineConfig({
    workers: 1
}

Several workers

If you want to run the test on several workers, you could set a seed to persist the faker generated data, example of implementation:

import {faker} from '@faker-js/faker/locale/nb_NO'

const {test, expect} = require('@playwright/test')
const { generateRandomUser } = require('../helpers')

const firstUser = generateRandomUser(11);
const secondUser = generateRandomUser(22);
const users = [firstUser, secondUser];

// parametrized test
for(const user of users) {
  const { username, email, password, seed } = user;
  faker.seed(seed)
  test.only(`should register ${username}`, async ({ page }) => {
    // Your code
  });
};

const { faker } = require('@faker-js/faker');

exports.generateRandomUser = (seed) => {
  faker.seed(seed)
  // For the seed to work, you cannot use math.random, but faker generated number
  // const random = Math.random().toString().slice(2, 6); 

  const random = faker.number.int({ min: 100, max: 100000 })
  let username = faker.lorem.word() + '_' + random;
  username = username.toLowerCase()
  const email = username + '@gmail.com';
  const password = faker.internet.password();

  return {
    username,
    email,
    password,
    seed
  }
}

I tried your code in base form and it is working fine

const {test, expect} = require('@playwright/test')
// const { generateRandomUser } = require('../helpers')

const firstUser = "firstUser";
const secondUser = "secondUser";
const users = [firstUser, secondUser];

// parametrized test
users.forEach(user => {
  console.log('USER', user);
  test(`should register ${user}`, async ({ page }) => {
    console.log(user);
  });
});

Output:

 $ npx playwright test example3.spec.ts

USER firstUser
USER secondUser

Running 2 tests using 1 worker

USER firstUser
USER secondUser
  ✓  1 example3.spec.ts:11:3 › should register firstUser (109ms)
firstUser
  ✓  2 example3.spec.ts:11:3 › should register secondUser (53ms)
secondUser

  2 passed (3.7s)

and I'm on Playwright version 1.35.1

I think generateRandomUser does not have any await, or is that function is async or not?

seems like your issue here is with username not getting defined till it is called which is failing the tests.

> ForEach loop doesn't await for the promises.

Use for- of loop instead:

async function printFiles () {
  const files = await getFilePaths();

  for await (const file of files) {
    const contents = await fs.readFile(file, 'utf8');
    console.log(contents);
  }
}

Reference: https://stackoverflow.com/a/37576787