Answer

Setting Up and Testing Internationalization in a React Web App with Playwright

First, you'll need to set up your React app for internationalization (i18n). This involves adding libraries like react-i18next or react-intl.

// Install the library
npm install react-i18next i18next

Next, create translation files or use an online service for your app's text content.

// Example of a translation file
{
  "welcome": "Welcome to our app!",
  "logout": "Log out"
}

Testing Internationalization with Playwright

With @playwright/test, you can mock different language settings and check if the correct translations are displayed.

import { test } from '@playwright/test';

test('displays correct translation', async ({ page }) => {
  await page.goto('https://ray.run');
  // Mock network requests or modify browser settings here
  // Check if the correct translation is displayed
});

You can also mock backend responses, allowing you to test the frontend without depending on the backend.

test('mocks backend response', async ({ page }) => {
  await page.route('https://ray.run/api/user', route => {
    route.fulfill({
      status: 200,
      body: JSON.stringify({ name: 'John Doe' }),
    });
  });
  await page.goto('https://ray.run');
  // Check if the frontend handles the mocked response correctly
});

This way, you can thoroughly test your app's i18n features without relying on real backend services. For more tips on efficient testing with Playwright, check out this blog post.