--- id: testing-library title: "Migrating from Testing Library" --- ## Migration principles This guide describes migration to Playwright's [Experimental Component Testing](./test-components) from [DOM Testing Library](https://testing-library.com/docs/dom-testing-library/intro/), [React Testing Library](https://testing-library.com/docs/react-testing-library/intro/), [Vue Testing Library](https://testing-library.com/docs/vue-testing-library/intro) and [Svelte Testing Library](https://testing-library.com/docs/svelte-testing-library/intro). :::note If you use DOM Testing Library in the browser (for example, you bundle end-to-end tests with webpack), you can switch directly to Playwright Test. Examples below are focused on component tests, but for end-to-end test you just need to replace `await mount` with `await page.goto('http://localhost:3000/')` to open the page under test. ::: ## Cheat Sheet | Testing Library | Playwright | |---------------------------------------------------------|-----------------------------------------------| | [screen](https://testing-library.com/docs/queries/about#screen) | [page](./api/class-page) and [component](./api/class-locator) | | [queries](https://testing-library.com/docs/queries/about) | [locators](./locators) | | [async helpers](https://testing-library.com/docs/dom-testing-library/api-async) | [assertions](./test-assertions) | | [user events](https://testing-library.com/docs/user-event/intro) | [actions](./api/class-locator) | | `await user.click(screen.getByText('Click me'))` | `await component.getByText('Click me').click()` | | `await user.click(await screen.findByText('Click me'))` | `await component.getByText('Click me').click()` | | `await user.type(screen.getByLabel('Password'), 'secret')` | `await component.getByLabel('Password').fill('secret')` | | `expect(screen.getByLabel('Password')).toHaveValue('secret')` | `await expect(component.getByLabel('Password')).toHaveValue('secret')` | | `screen.findByText('...')` | `component.getByText('...')` | | `screen.getByTestId('...')` | `component.getByTestId('...')` | | `screen.queryByPlaceholderText('...')` | `component.getByPlaceholder('...')` | | `screen.getByRole('button', { pressed: true })` | `component.getByRole('button', { pressed: true })`| ## Example Testing Library: ```js import React from 'react'; import { render, screen } from '@testing-library/react'; import userEvent from '@testing-library/user-event'; test('should sign in', async () => { // Setup the page. const user = userEvent.setup(); render(); // Perform actions. await user.type(screen.getByLabel('Username'), 'John'); await user.type(screen.getByLabel('Password'), 'secret'); await user.click(screen.getByText('Sign in')); // Verify signed in state by waiting until "Welcome" message appears. await screen.findByText('Welcome, John'); }); ``` Line-by-line migration to Playwright Test: ```js const { test, expect } = require('@playwright/experimental-ct-react'); // 1 test('should sign in', async ({ page, mount }) => { // 2 // Setup the page. const component = await mount(); // 3 // Perform actions. await component.getByText('Username').fill('John'); // 4 await component.getByText('Password').fill('secret'); await component.getByText('Sign in').click(); // Verify signed in state by waiting until "Welcome" message appears. await expect(component.getByText('Welcome, John')).toBeVisible(); // 5 }); ``` Migration highlights (see inline comments in the Playwright Test code snippet): 1. Import everything from `@playwright/experimental-ct-react` (or -vue, -svelte) for component tests, or from `@playwright/test` for end-to-end tests. 1. Test function is given a `page` that is isolated from other tests, and `mount` that renders a component in this page. These are two of the [useful fixtures](./api/class-fixtures) in Playwright Test. 1. Replace `render` with `mount` that returns a [component locator](./locators). 1. Use locators created with [`method: Locator.locator`] or [`method: Page.locator`] to perform most of the actions. 1. Use [assertions](./test-assertions) to verify the state. ## Migrating queries All queries like `getBy...`, `findBy...`, `queryBy...` and their multi-element counterparts are replaced with `component.getBy...` locators. Locators always auto-wait and retry when needed, so you don't have to worry about choosing the right method. When you want to do a [list operation](./locators#lists), e.g. assert a list of texts, Playwright automatically performs multi-element operations. ## Replacing `waitFor` Playwright includes [assertions](./test-assertions) that automatically wait for the condition, so you don't usually need an explicit `waitFor`/`waitForElementToBeRemoved` call. ```js // Testing Library await waitFor(() => { expect(getByText('the lion king')).toBeInTheDocument(); }); await waitForElementToBeRemoved(() => queryByText('the mummy')); // Playwright await expect(page.getByText('the lion king')).toBeVisible(); await expect(page.getByText('the mummy')).toBeHidden(); ``` When you cannot find a suitable assertion, use [`expect.poll`](./test-assertions#polling) instead. ```js await expect.poll(async () => { const response = await page.request.get('https://api.example.com'); return response.status(); }).toBe(200); ``` ## Replacing `within` You can create a locator inside another locator with [`method: Locator.locator`] method. ```js // Testing Library const messages = document.getElementById('messages'); const helloMessage = within(messages).getByText('hello'); // Playwright const messages = component.locator('id=messages'); const helloMessage = messages.getByText('hello'); ``` ## Playwright Test Super Powers Once you're on Playwright Test, you get a lot! - Full zero-configuration TypeScript support - Run tests across **all web engines** (Chrome, Firefox, Safari) on **any popular operating system** (Windows, macOS, Ubuntu) - Full support for multiple origins, [(i)frames](./api/class-frame), [tabs and contexts](./pages) - Run tests in isolation in parallel across multiple browsers - Built-in test [artifact collection](./test-use-options.md#recording-options) You also get all these ✨ awesome tools ✨ that come bundled with Playwright Test: - [Playwright Inspector](./debug.md) - [Playwright Test Code generation](./codegen-intro.md) - [Playwright Tracing](./trace-viewer.md) for post-mortem debugging ## Further Reading Learn more about Playwright Test runner: - [Getting Started](./intro) - [Experimental Component Testing](./test-components) - [Locators](./locators.md) - [Assertions](./test-assertions) - [Auto-waiting](./actionability)