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# Writing Tests

So you'd like to write new tests for WPT? Great! For starters, we recommend

reading [the introduction](../index) to learn how the tests are organized and

interpreted. You might already have an idea about what needs testing, but it's

okay if you don't know where to begin. In either case, [the guide on making a

testing plan](making-a-testing-plan) will help you decide what to write.

There's also a load of [general guidelines](general-guidelines) that apply to all tests.

## Test Types

There are various different ways of writing tests:

* [JavaScript tests (testharness.js)](testharness) are preferred for testing APIs and may be used

  for other features too. They are built with the testharness.js unit testing framework, and consist

  of assertions written in JavaScript. A high-level [testharness.js tutorial](testharness-tutorial)

  is available.

* Rendering tests should be used to verify that the browser graphically

  displays pages as expected. See the [rendering test guidelines](rendering)

  for tips on how to write great rendering tests. There are a few different

  ways to write rendering tests:

  * [Reftests](reftests) should be used to test rendering and layout. They

    consist of two or more pages with assertions as to whether they render

    identically or not. A high-level [reftest tutorial](reftest-tutorial) is available. A

    [print reftests](print-reftests) variant is available too.

  * [Visual tests](visual) should be used for checking rendering where there is

    a large number of conforming renderings such that reftests are impractical.

    They consist of a page that renders to final state at which point a

    screenshot can be taken and compared to an expected rendering for that user

    agent on that platform.

* [Crashtests](crashtest) tests are used to check that the browser is

  able to load a given document without crashing or experiencing other

  low-level issues (asserts, leaks, etc.). They pass if the load

  completes without error.

* [wdspec](wdspec) tests are written in Python using

  [pytest](https://docs.pytest.org/en/latest/) and test [the WebDriver browser

  automation protocol](https://w3c.github.io/webdriver/)

* [Manual tests](manual) are used as a last resort for anything that can't be

  tested using any of the above. They consist of a page that needs manual

  interaction or verification of the final result.

See [file names](file-names) for test types and features determined by the file names,

and [server features](server-features) for advanced testing features.

## Submitting Tests

Once you've written tests, please submit them using

the [typical GitHub Pull Request workflow](submission-process); please

make sure you run the [`lint` script](lint-tool) before opening a pull request!

## Table of Contents

```eval_rst

.. toctree::

   :maxdepth: 1

   general-guidelines

   making-a-testing-plan

   testharness

   testharness-tutorial

   rendering

   reftests

   reftest-tutorial

   print-reftests

   visual

   crashtest

   wdspec

   manual

   file-names

   server-features

   submission-process

   lint-tool

   ahem

   assumptions

   css-metadata

   css-user-styles

   h2tests

   testdriver

   testdriver-extension-tutorial

   tools

   test-templates

   github-intro

   ../tools/webtransport/README.md

```