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diff --git a/browser/components/urlbar/docs/testing.rst b/browser/components/urlbar/docs/testing.rst new file mode 100644 index 0000000000..a56bd297a7 --- /dev/null +++ b/browser/components/urlbar/docs/testing.rst @@ -0,0 +1,216 @@ +Testing +======= +This documentation discusses how to write a test for the address bar and the +different test utilities that are useful when writing a test for the address +bar. + +Common Tests +------------ +Mochitests +~~~~~~~~~~ +Some common tests for the address bar are the **mochitests**. The purpose of +a mochitest is to run the browser itself. Mochitests can be called +"browser tests", "mochitest-browser-chrome", or +"browser-chrome-mochitests". There are other types of mochitests that are not +for testing the browser and therefore can be ignored for the purpose of the +address bar. An example of a mochitest is +`tests/browser/browser_switchTab_currentTab.js <https://searchfox.org/mozilla- +central/source/browser/components/urlbar/tests/browser/browser_switchTab_ +currentTab.js>`_ + +XPCShell +~~~~~~~~ +`XPCShell Tests <https://firefox-source-docs.mozilla.org/testing/xpcshell/index +.html>`_ are another type of test relevant to the address bar. XPCShell tests +are often called unit tests because they tend to test specific modules or +components in isolation, as opposed the mochitest which have access to the full +browser chrome. + +XPCShell tests do not use the browser UI and are completely separate from +browser chrome. XPCShell tests are executed in a JavaScript shell that is +outside of the browser. For historical context, the "XPC" naming convention is +from XPCOM (Cross Platform Component Model) which is an older framework that +allows programmers to write custom functions in one language, such as C++, and +connect it to other components in another language, such as JavaScript. + +Each XPCShell test is executed in a new shell instance, therefore you will +see several Firefox icons pop up and close when XPCShell tests are executing. +These are two examples of XPCShell tests for the address bar +`test_providerHeuristicFallback <https://searchfox.org/mozilla-central/source +/browser/components/urlbar/tests/unit/test_providerHeuristicFallback.js>`_ +and +`test_providerTabToSearch <https://searchfox.org/mozilla-central/source/browser +/components/urlbar/tests/unit/test_providerTabToSearch.js>`_. + +When To Write a XPCShell or Mochitest? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Always default to writing an XPCShell test if it is possible. XPCShell +tests are faster to execute than browser tests. Although, most of the time you +will write a browser test because you could be modifying something in the UI or +testing a specific component in the UI. + +If you are writing a test for a urlbarProvider, you can test the Provider +through a XPCShell test. Providers do not modify the UI, instead what they do is +receive a url string query, search for the string and bring back the result. An +example is the `ProviderPlaces <https://searchfox.org/mozilla-central/sou +rce/browser/components/urlbar/UrlbarProviderPlaces.jsm>`_, which fetches +results from the Places database. Another component that’s good for writing +XPCShell test is the `urlbarMuxer <https://searchfox.org/mozilla-central/ +source/browser/components/urlbar/UrlbarMuxerUnifiedComplete.jsm>`_. + +There may be times where writing both an XPCShell test and browser test is +necessary. In these situations, you could be testing the result from a Provider +and also testing what appears in the UI is correct. + +How To Write a Test +------------------- + +Test Boilerplate +~~~~~~~~~~~~~~~~ +This basic test boilerplate includes a license code at the top and this license +code is present at the top of every test file, the ``"use strict"`` string is +to enable strict mode in JavaScript, and ``add_task`` function adds tests to be +executed by the test harness. + +.. code-block:: javascript + + /* Any copyright is dedicated to the Public Domain. + * http://creativecommons.org/publicdomain/zero/1.0/ */ + + /** + * This tests ensures that the urlbar ... + */ + + "use strict"; + + add_task(async function testOne() { + // testing code and assertions + }); + + add_task(async function testTwo() { + // testing code and assertions + }); + +In order to run a test use the ``./mach`` command, for example, ``./mach test <path to test +file>`` to run test locally. Use the command with ``--jsdebugger`` argument at +the end to open the DevTools debugger to step through the test, ``./mach test +<path to test> --jsdebugger``. + +Manifest +~~~~~~~~ +The manifest's purpose is to list all the test in the directory and dictate to +the test harness which files are test and how the test harness should run these +test. Anytime a test is created, the test file name needs to be added to the +manifest in alphabetical order. + +Start in the manifest file and add your test name in alphabetical +order. The manifest file we should add our test in is +`browser.ini <https://searchfox.org/mozilla-central/source/browser/components/ +urlbar/tests/browser/browser.ini>`_. The ``urlbar/test/browser/`` directory +is the main browser test directory for address bar, and the manifest file +linked above is the main browser test manifest. +The ``.ini`` file extension is an initialization file for Windows or MS-DOS. + +Manifest Metadata +~~~~~~~~~~~~~~~~~ +The manifest file can define common keys/metadata to influence the test's +behavior. For example, the metadata ``support-files`` are a list of additional +files required to run a test. Any values assigned to the key ``support-files`` +only applies to the single file directly above the ``support-files`` key. +If more files require ``support-files``, then ``support-files`` need to be +added directly under the other test file names. Another example of a manifest +metadata is ``[DEFAULT]``. Anything under ``[DEFAULT]`` will be picked up by +all tests in the manifest file. + +For information on all the manifest metadata available, please visit +:doc:`/build/buildsystem/test_manifests`. + +Common Test Utilities +--------------------- +This section describes common test utilities which may be useful when writing a +test for the address bar. Below are a description of common utils where you can +find helpful testing methods. + +Many test utils modules end with ``TestUtils.jsm``. However not every testing +function will end with ``TestUtils.jsm``. For example, `PlacesUtils <https:// +searchfox.org/mozilla-central/source/toolkit/components/places/PlacesUtils. +jsm>`_ does not have “Test” within its name. + +A critical function to remember is the ``registerCleanupFunction`` within +the ``head.js`` file mentioned below. This function's purpose may be to clean +up the history or any other clean ups that are necessary after your test is +complete. Cleaning up after a browser test is necessary because clean up +ensures what is done within one test will not affect subsequent tests. + +head.js and common-head.js +~~~~~~~~~~~~~~~~~~~~~~~~~~ +The `head.js <https://searchfox.org/mozilla-central/source/browser/components +/urlbar/tests/browser/head.js>`_ file is executed at the beginning before each +test and contains imports to modules which are useful for each test. +Any tasks ``head.js`` adds (via add_task) will run first for each test, and +any variables and functions it defines will be available in the scope of +each test. This file is small because most of our Utils are actually in other +`.jsm` files. + +The ``XPCOMUtils.defineLazyModuleGetters`` method within ``head.js`` sets up +modules names to where they can be found, their paths. ``Lazy`` means the files +are only imported if or when it is used. Any tests in this directory can use +these modules without importing it themselves in their own file. +The ``head.js`` provides a convenience for this purpose. The ``head.js`` file +imports `common-head.js <https://searchfox.org/mozilla-central/source/browser/components/urlbar/tests/browser/head-common.js>`_ +making everything within ``head-common.js`` available in ``head.js`` as well. + +The ``registerCleanupFunction`` is an important function in browser mochi tests +and it is part of the test harness. This function registers a callback function +to be executed when your test is complete. The purpose may be to clean up the +history or any other clean ups that are necessary after your test is complete. +For example, browser mochi tests are executed one after the other in the same +window instance. The global object in each test is the browser ``window`` +object, for example, each test script runs in the browser window. +If the history is not cleaned up it will remain and may affect subsequent +browser tests. For most test outside of address bar, you may not need to clear +history. In addition to cleanup, ``head.js`` calls the +``registerCleanupFunction`` to ensure the urlbar panel is closed after each +test. + +UrlbarTestUtils +~~~~~~~~~~~~~~~ +`UrlbarTestUtils.sys.mjs <https://searchfox.org/mozilla-central/source/browser/components/urlbar/tests/UrlbarTestUtils.sys.mjs>`_ is useful for url bar testing. This +file contains methods that can help with starting a new search in the url bar, +waiting for a new search to complete, returning the results in +the view, and etc. + +BrowserTestUtils +~~~~~~~~~~~~~~~~ +`BrowserTestUtils.sys.mjs <../../testing/browser-chrome/browsertestutils.html>`_ +is useful for browser window testing. This file contains methods that can help +with opening tabs, waiting for certain events to happen in the window, opening +new or private windows, and etc. + +TestUtils +~~~~~~~~~ +`TestUtils.jsm <../../testing/testutils.html>`_ is useful for general +purpose testing and does not depend on the browser window. This file contains +methods that are useful when waiting for a condition to return true, waiting for +a specific preference to change, and etc. + +PlacesTestUtils +~~~~~~~~~~~~~~~ +:searchfox:`PlacesTestUtils.sys.mjs <toolkit/components/places/tests/PlacesTestU +tils.sys.mjs>` is useful for adding visits, adding +bookmarks, waiting for notification of visited pages, and etc. + +EventUtils +~~~~~~~~~~ +`EventUtils.js <https://searchfox.org/mozilla-central/source/testing/mochitest +/tests/SimpleTest/EventUtils.js>`_ is an older test file and does not +need to be imported because it is not a ``.jsm`` file. ``EventUtils`` is only +used for browser tests, unlike the other TestUtils listed above which are +used for browser tests, XPCShell tests and other tests. + +All the functions within ``EventUtils.js`` are automatically available in +browser tests. This file contains functions that are useful for synthesizing +mouse clicks and keypresses. Some commonly used functions are +``synthesizeMouseAtCenter`` which places the mouse at the center of the DOM +element and ``synthesizeKey`` which can be used to navigate the view and start +a search by using keydown and keyenter arguments. |