What are the best practices for structuring API tests with Playwright?

Answer

Best Practices for Structuring API Tests with Playwright

Test User-Visible Behavior

Focus on verifying that the application code works for end users. Interact with the rendered output on the page, just like your users would.

Isolate Tests

Ensure each test is independent, with its own local storage, session storage, data, and cookies. This improves reproducibility, debugging, and prevents cascading failures.

Use Hooks

Utilize before and after hooks to avoid repetition and keep tests isolated. For example, use a before hook to navigate to a specific URL or log in before each test.

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

test.beforeEach(async ({ page }) => {
  await page.goto('https://ray.run/');
});

test('example test', async ({ page }) => {
  // Your test code here
});

Allow Some Duplication

It's acceptable to have some duplication in simple tests if it makes them clearer and easier to maintain.

Use APIRequestContext Methods

With Playwright Test, use the built-in request fixture for API testing. Create APIRequestContext methods for tasks like testing server APIs or validating post-conditions after browser actions.

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

test('API test example', async ({ request }) => {
  const response = await request.post('https://ray.run/api/some-endpoint', {
    json: { key: 'value' },
  });

  expect(response.status()).toBe(200);
  expect(await response.json()).toEqual({ result: 'success' });
});

By following these best practices, you'll create well-structured and organized API tests with Playwright.