How do I use Playwright's experimental Component Testing library to test components and make assertions?

Answer

Extend Expect Assertions for Components

To extend expect assertions for components in Playwright, you can use the experimental Component Testing library. This library allows you to mount components and interact with them using Playwright's API. You can then make assertions about the component's state using the expect function.

First, install the necessary packages:

npm install @playwright/test @playwright/experimental-ct-react

Next, create a test file and import the required functions:

import { test } from '@playwright/test';
import { mount } from '@playwright/experimental-ct-react';
import MyComponent from './MyComponent';

Now, define a test case and mount your component:

test('interact with component and make assertions', async ({ page }) => {
  const component = await mount(page, <MyComponent />);
  
  // Interact with the component using Playwright's API
  await page.fill('input', 'Hello, World!');
  
  // Make assertions about the component's state
  expect(component).toHaveValue('Hello, World!');
  expect(component).toContainText('Hello, World!');
});

Remember that the browser context is shared across all tests in the file, so avoid relying on global state changes made by previous tests.

By using Playwright's experimental Component Testing library, you can extend expect assertions for components, interact with them, and make assertions about their states. For more tips on writing efficient Playwright test scripts, check out this blog post.