How to add Playwright tests | Contribute

Installation

Playwright is installed with the repository dependencies, but its browser binaries must be installed separately. Run this command before your first local test run and after Playwright is upgraded. On Linux, it also installs the required system dependencies:

pnpm run playwright:install-build-tools

To learn how to write Playwright tests, or ‘specs’, please see Playwright’s official documentation.

Where to Add a Test

Playwright tests are in the ./e2e directory.
Standard Playwright test specs use the .spec.ts extension.

Best Practices for writing E2E tests

This section will explain in detail about best practices for writing and documenting E2E tests based on Playwright documentation and our community code-style.

Imports

Import test and expect from @playwright/test for tests that do not change user data:

For example:

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

Tests that change user data should use the isolated-user fixture. It creates a separate user for the test and deletes that user afterward. Import test and expect from the fixture, then select a user preset if the test needs one:

import { test, expect } from './fixtures/isolated-user';

test.use({ userPreset: 'certified' });

Identifying a DOM element

Playwright comes with multiple built-in locators, but we recommend prioritizing the following locators:

getByRole for querying semantic elements, whose role is important and allows assistive technology to perceive the page correctly.
getByLabel for querying form controls by their associated label.
getByPlaceholder for querying form controls when no label is available.
getByAltText for querying images and other elements by their alternative text.
getByText for querying non-semantic elements such as div, span, or p.

For example:

await expect(page.getByRole('heading', { name: 'Sign up' })).toBeVisible();
await expect(page.getByText('Hello World')).toBeVisible();

If an element cannot be queried with an appropriate user-facing locator, you can use the data-playwright-test-label attribute as a last resort. This attribute should be used only in Playwright tests, and not for styling or any other purposes.

For example:

<div data-playwright-test-label="landing-page-figure">
  <img src="..." alt="..." />
</div>

In the test file, you can use the getByTestId method to identify the element.

For example:

await expect(page.getByTestId('landing-page-figure')).toBeVisible();

Constants

Define any constant elements, data sets, or configurations used throughout your tests for easy reference.

For example:

const landingPageElements = { ... };
const superBlocks = [ ... ];

Descriptive test names

Each test block should have a clear and concise name describing exactly what it’s testing.

For example:

test('The component landing-top renders correctly', async ({ page }) => {
  // ...
});

Human readable assertions

Each assertion should be as human readable as possible. This makes it easier to understand what the test is doing and what it’s expecting.

For example:

await expect(
  page.getByRole('heading', { level: 1, name: 'Learn to code — for free.' })
).toBeVisible();

Keep it DRY

Make sure that the tests are not repeating the same code over and over again. If you find yourself repeating the same code, consider refactoring it as a loop or a function.

For example:

const expectedLogoCount = 3;
await expect(logos).toHaveCount(expectedLogoCount);

for (const logo of await logos.all()) {
  await expect(logo).toBeVisible();
}

Tests for mobile screens

Use the isMobile argument to test logic that is specific to mobile devices.

For example:

test('The campers landing page figure is visible on desktop and hidden on mobile view', async ({
  page,
  isMobile
}) => {
  const landingPageFigure = page.getByTestId('landing-page-figure');

  if (isMobile) {
    await expect(landingPageFigure).toBeHidden();
  } else {
    await expect(landingPageFigure).toBeVisible();
  }
});

Group related tests together using test.describe blocks. This makes it easier to understand what the tests are doing and what they’re testing.

For example:

test.describe('The campers landing page', () => {
  test('The campers landing page figure is visible on desktop and hidden on mobile view', async ({
    isMobile
  }) => {
    // ...
  });

  test('The campers landing page figure has the correct image', async () => {
    // ...
  });
});

How to Run Tests

Ensure that MongoDB and Client Applications are Running

Playwright’s setup project creates the shared certified and development users before the tests run. Tests that import the isolated-user fixture create and remove their own users.

Run the Playwright Tests

To run tests with Playwright, check the following commands:

To run tests in UI mode:
```
pnpm playwright:watch
```

To run a single test:

pnpm playwright:run <filename>

For example:

pnpm playwright:run landing.spec.ts

To run a set of test files:

pnpm playwright:run <filename1> <filename2>

For example:

pnpm playwright:run action-row.spec.ts landing.spec.ts

Run the test with the title:

pnpm playwright:run -g "<title>"

For example:

pnpm playwright:run -g "add a todo item"

Debugging Tests

Since Playwright runs in Node.js, you can debug it with your debugger of choice e.g. using console.log or inside your IDE

Debugging all tests:
```
pnpm playwright:run --debug
```

Debugging one test file:

pnpm playwright:run example.spec.ts --debug

Generate Test Reports

The HTML Reporter shows you a full report of your tests allowing you to filter the report by browsers, passed tests, failed tests, skipped tests and flaky tests.

pnpm --dir e2e exec playwright show-report playwright/reporter

Troubleshooting

Playwright reports a connection error when the client is not available at its configured base URL. The default URL is http://127.0.0.1:8000.

  Error: page.goto: Could not connect: Connection refused
  =========================== logs ===========================
  navigating to "http://127.0.0.1:8000/", waiting until "load"
  ============================================================

Check these items before running the test again:

Confirm that the client and API are running.
Open http://127.0.0.1:8000 in your browser.
If you changed HOME_LOCATION, confirm that it points to the running client.

For other errors, see Playwright’s test debugging guide.

Set up for Playwright on GitHub Codespaces

Ensure Development Environment is Running

Follow the GitHub Codespaces setup instructions. The codespace creates .env, starts MongoDB and Mailpit, and seeds the database. Playwright creates its test users when the tests run.

Start the client and API if they are not already running:

pnpm run develop

Install Playwright Build Tools

To install necessary dependencies for running Playwright run the following command:

pnpm run playwright:install-build-tools

Run the Playwright Tests on GitHub Codespaces

To run all Playwright tests, run the following command:

pnpm playwright:run