Writing good test cases

Should have some tips here about how to make a test which is easy to know when it succeeds, things like a 100x100 green block, just printing SUCCESS or FAILURE, and using dumpAsText().

Should remind folks to write tests that work both in Safari and in DRT. The trick is to test for the existence of a special object like layoutTestController before using it. An example:

if (window.layoutTestController)
    layoutTestController.dumpAsText()

• Do not use fonts other than those bundled with Mac OS X (usually there's no need to specify font families in a test). The only exception to this is the Ahem font.

• Tests should not access the Internet. Avoid http: URLs in src and href attributes, in CSS properties and in XMLHttpRequest. Testing WebKit's network layer should be done using the HTTP test facility, to be described below.

• Do not make unnecessary use of window.setTimeout and similar functions which create a lower bound on the time it takes the test to complete. For separating events in time, you can use eventSender.leapForward.

• Do not make unnecessary use of external resources: use inline JavaScript and style elements instead of links to external stylesheets. You can also use data: URLs sometimes for things like frames' src attribute. The exceptions are stylesheets and JavaScript libraries that are shared by multiple tests, and cases that test the loading of external resources.

DumpRenderTree JavaScript Environment

DumpRenderTree exposes a number of additional JavaScript objects in the testing environment.

These can be used to perform additional debugging-related tasks.

window.layoutTestController

dumpAsText()

Call this method to make your test output plain text instead of a render tree. This is useful if your test prints messages rather than testing fancy layout. For an example of how to print to a console in a test, check out LayoutTests/fast/dom/ Element/attribute-uppercase.html.

waitUntilDone() and notifyDone()

By default, DumpRenderTree dumps each test file immediately after the document has loaded and the load event handlers have executed. If your test needs to do further processing after loading -- for example, waiting for a timer to fire -- call layoutTestController.waitUntilDone() to tell DumpRenderTree to delay its dump, and then call notifyDone when your results are ready.

window.eventSender

mouseMoveTo(x, y)

Used to change the current mouse position.

leapForward(ms)

Jumps the current event time forward by a specified number of miliseconds.

mouseDown()

Sends a mouseDown event to the WebView at the current mouse position.

mouseUp()

Sends a mouseUp event to the WebView at the current mouse position.

window.GCController

collect()

Performs JavaScript garbage collection.

collectOnAlternateThread(wait)

Performs JavaScript garbage collection on an alternate thread. The wait argument specifies whether script execution waits for garbage collection to finish.

window.textInputController

Needs to be filled in.

insertText

doCommand

setMarkedText

substringFromRange

attributedSubstringFromRange

firstRectForCharacterRange

characterIndexForPoint

makeAttributedString

window.appleScriptController

doJavaScript()

Needs to be filled in.

window.navigationController

The navigation controller is currently broken. ​http://bugs.webkit.org/show_bug.cgi?id=11042

evalAfterBackForwardNavigation(script [, destination])

To test a bug having to do with the loader or the back/forward cache, call this method to run a script after executing a back/forward navigation. The first argument is the script to run, and the second argument is the page to load during the navigation. The second argument is optional. It defaults to about:blank.

Writing tests which require network access

run-webkit-tests (the script which runs DumpRenderTree) also launches a local Apache daemon (httpd) to allow real local-only network based testing (for incremental loads, XMLHttpRequest, etc.) ap needs to document how best to use this.