playwright/CONTRIBUTING.md

Contributing

• How to Contribute
  • Getting Code
  • Code reviews
  • Code Style
  • API guidelines
  • Commit Messages
  • Writing Documentation
  • Adding New Dependencies
  • Running & Writing Tests
  • Public API Coverage
• Contributor License Agreement
  • Code of Conduct

How to Contribute

Getting Code

1. Clone this repository

git clone https://github.com/microsoft/playwright
cd playwright

2. Install dependencies

npm install

3. Run all Playwright tests locally. For more information about tests, read Running & Writing Tests.

npm test

Code reviews

All submissions, including submissions by project members, require review. We use GitHub pull requests for this purpose. Consult GitHub Help for more information on using pull requests.

Code Style

• Coding style is fully defined in .eslintrc
• Comments should be generally avoided. If the code would not be understood without comments, consider re-writing the code to make it self-explanatory.

To run code linter, use:

npm run eslint

API guidelines

When authoring new API methods, consider the following:

• Expose as little information as needed. When in doubt, don’t expose new information.
• Methods are used in favor of getters/setters.
  • The only exception is namespaces, e.g. page.keyboard and page.coverage
• All string literals must be small case. This includes event names and option values.
• Avoid adding "sugar" API (API that is trivially implementable in user-space) unless they're very common.

Commit Messages

Commit messages should follow the Semantic Commit Messages format:

label(namespace): title

description

footer

1. label is one of the following:
   • fix - playwright bug fixes.
   • feat - playwright features.
   • docs - changes to docs, e.g. docs(api.md): .. to change documentation.
   • test - changes to playwright tests infrastructure.
   • devops - build-related work, e.g. CI related patches and general changes to the browser build infrastructure
   • chore - everything that doesn't fall under previous categories
2. namespace is put in parenthesis after label and is optional. Must be lowercase.
3. title is a brief summary of changes.
4. description is optional, new-line separated from title and is in present tense.
5. footer is optional, new-line separated from description and contains "fixes" / "references" attribution to github issues.

Example:

fix(firefox): make sure session cookies work

This patch fixes session cookies in firefox browser.

Fixes #123, fixes #234

Writing Documentation

All public API should have a descriptive entry in docs/api.md. There's a documentation linter which makes sure documentation is aligned with the codebase.

To run the documentation linter, use:

npm run doc

Adding New Dependencies

For all dependencies (both installation and development):

• Do not add a dependency if the desired functionality is easily implementable.
• If adding a dependency, it should be well-maintained and trustworthy.

A barrier for introducing new installation dependencies is especially high:

• Do not add installation dependency unless it's critical to project success.

Running & Writing Tests

• Every feature should be accompanied by a test.
• Every public api event/method should be accompanied by a test.
• Tests should be hermetic. Tests should not depend on external services.
• Tests should work on all three platforms: Mac, Linux and Win. This is especially important for screenshot tests.

Playwright tests are located in test/test.js and are written with a TestRunner framework. These are integration tests, making sure public API methods and events work as expected.

• To run all tests:

npm run test

• To run all tests in Chromium

npm run ctest # also `ftest` for firefox and `wtest` for WebKit

• To run tests in parallel, use -j flag:

npm run wtest -- -j 4

• To run tests in "verbose" mode or to stop testrunner on first failure:

npm run ftest -- --verbose
npm run ftest -- --break-on-failure

• To run a specific test, substitute the it with fit (mnemonic rule: 'focus it'):

...
// Using "fit" to run specific test
fit('should work', async ({server, page}) => {
  const response = await page.goto(server.EMPTY_PAGE);
  expect(response.ok).toBe(true);
});

• To disable a specific test, substitute the it with xit (mnemonic rule: 'cross it'):

...
// Using "xit" to skip specific test
xit('should work', async ({server, page}) => {
  const response = await page.goto(server.EMPTY_PAGE);
  expect(response.ok).toBe(true);
});

• To run tests in non-headless (headful) mode:

HEADLESS=false npm run ctest

• To run tests with custom browser executable, specify CRPATH, WKPATH or FFPATH env variable that points to browser executable:

CRPATH=<path-to-executable> npm run ctest

• To run tests in slow-mode:

HEADLESS=false SLOW_MO=500 npm run wtest

• To debug a test, "focus" a test first and then run:

BROWSER=chromium node --inspect-brk test/test.js

• When should a test be marked with skip or fail?

  • skip(condition): This test should never work for condition where condition is usually a certain browser like FFOX (for Firefox), WEBKIT (for WebKit), and CHROMIUM (for Chromium).

    For example, the alt-click downloads test is marked with skip(FFOX) since an alt-click in Firefox will not produce a download even if a person was driving the browser.

  • fail(condition): This test should eventually work for condition where condition is usually a certain browser like FFOX (for Firefox), WEBKIT (for WebKit), and CHROMIUM (for Chromium).

    For example, the alt-click downloads test is marked with fail(CHROMIUM || WEBKIT) since Playwright performing these actions currently diverges from what a user would experience driving a Chromium or WebKit.

Public API Coverage

Every public API method or event should be called at least once in tests. To ensure this, there's a coverage command which tracks calls to public API and reports back if some methods/events were not called.

Run all tests for all browsers with coverage enabled:

npm run coverage

There are also per-browser commands:" npm run ccoverage, npm run fcoverage and npm run wcoverage.

Contributor License Agreement

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com.

When you submit a pull request, a CLA bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., status check, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.