Acid2

The reference image for Acid2. In the real test, the nose will light up blue when pointing over it with the cursor.

Software Testing Portal

Acid2 is a test suite published and promoted by the Web Standards Project to identify web page rendering flaws in browsers and authoring tools. Acid2 was released on April 12, 2005.^[1] It has been developed in the spirit of the Acid1 test from 1998. ^[2] The Acid tests test many features on a single page and report test results graphically.

Acid2 tests features of HTML and, more prominently, CSS. The purpose of testing such features is to highlight the problems with browsers that do not display it correctly. The Acid2 test should render correctly on any browser that follows the W3C HTML and CSS 2.0 specifications. Because Acid2 tests how web browsers deal with faulty code, the test is intentionally not written to W3C CSS standard specifications, and fails validation.^[3] This is expected and was the intention of its designers.^[4]

Overview of standards tested

Acid2 tests the following web standards:^[5]

• Alpha transparency on PNG images – the eyes are transparent PNGs
• The object element
• Absolute, relative and fixed positioning using CSS
• The CSS box model
• CSS tables
• CSS margins
• CSS generated content
• CSS parsing – Acid2 includes a number of illegal CSS statements to test error handling
• Paint order
• CSS line heights
• Hovering effects

Because Acid2 is not a comprehensive test, it does not guarantee total conformance with any particular standard.^[5]

The Web Standards Project has created a special version of Acid2 test,^[6] because the data: URIs used in the original test have never been formally standardized.

Compliant applications

Acid2 as rendered by compliant applications

If rendered correctly, Acid2 will appear as a smiley face below the text "Hello World!" in the user's browser, with the nose turning blue when the mouse cursor hovers over it. At the time of the test's release, no browsers could render Acid2 correctly, but now a number of applications pass the test by rendering it correctly:

Officially released

• WebKit- and KHTML-based browsers
  • Safari, the web browser included in Mac OS X
  • OmniWeb, a web browser for Mac OS X
  • Shiira, a web browser for Mac OS X
  • iCab, a web browser for Mac OS X
  • Konqueror, a web browser for KDE
• Prince, an XML-to-PDF converter for Windows and Linux
• Presto-based browsers
  • Opera, a web browser for Windows, Mac OS X, Linux, and BSD
  • Internet Channel, a version of the Opera browser for the Nintendo Wii game console.

In development

• Gecko 1.9 based applications
  • Mozilla Firefox 3, a web browser for Windows, Mac OS X and Linux
  • SeaMonkey 2, an all-in-one internet application suite for Windows, Mac OS X and Linux
  • Mozilla Prism, a web application platform for Windows, Mac OS X and Linux
• Tkhtml Html Viewer 3, a web browser for Windows and Linux
• Internet Explorer 8^[7]

  Non-compliant applications

  Although Internet Explorer has also been moving towards better CSS compliance, the current release version, Internet Explorer 7, doesn't pass the Acid2 test. While that version of the browser was in beta testing, Chris Wilson, the Internet Explorer Platform Architect, described Acid2 as a "wish list" of features rather than a true test of standards compliance, and that passing Acid2 was not an identified priority.^[8] Internet Explorer 8 Beta 1, released on March 5 2008, passed the official test^[9]. However, it only renders the image correctly when tested against the official website, which is located at http://www.webstandards.org/files/acid2/test.html. If the "www" part is omitted, or a copy of the test is run on another site, such as http://acid2.acidtests.org it does not.^[10] The reason is that the browser does not apply fallback mechanisms to the object element if its "data" attribute does not reference the same domain the test is hosted at, which causes a subtle difference between the official test and others. Microsoft has claimed that this was done to prevent a potential cross-domain security issue, and stated that they are looking into whether this restriction can be loosened in a future beta.

  Browsers based on the stable version of the Gecko layout engine, such as Firefox, Camino, and SeaMonkey, do not pass. Acid2 support exists on the pre-released versions of the next version of Gecko (v1.9), however, and so future versions of the mentioned browsers are expected to pass the test successfully. This includes Mozilla Firefox 3 alpha 2 and all subsequent releases.^[11]

  The PlayStation 3 web browser, based on NetFront, also fails the test.

  Ieacid2.png Acid2 as rendered by Internet Explorer 6.0	Acid2 as rendered by Internet Explorer 7.0	Acid2 NS72.png Acid2 as rendered by Mozilla Firefox 1.0, Mozilla 1.7.13, and Netscape 7.2	Firefoxacid2.png Acid2 as rendered by Mozilla Firefox 1.5 and 2.0
  Acid2 in Opera Mini 4.png Acid2 as rendered by Opera Mini 4

  Passing conditions

  A passing score is only considered valid if the browser's default settings were used. Changing font sizes, zoom level, applying user stylesheets, etc. can break the display of the test. This is expected and is not relevant to a browser's compliance.^[12]

  Ian Hickson, the author of the test, has provided WaSP with clarifications about the Acid2 test and how things should behave.^[13]

  The following browser settings and user actions may affect the rendering of Acid2 page without bearing on the browser's compliance:

  • Scrolling. A part of the face remains fixed when you scroll.
  • Zooming to any level other than 100% (default).
  • Disabling images.
  • Opera's Fit to width and SSR (Small Screen Rendering) modes. These are off by default, and the test is not valid when they are enabled.
  • User colors, fonts etc.
  • User style sheets, Opera's user mode for styling.
  • User JavaScripts.

  Timeline of compliant and partially compliant browsers

  The Acid2 test was announced by Håkon Wium Lie on March 16, 2005. ^[14] The test was coded by Ian Hickson in collaboration with the Web Standards Project and the larger web community. The test was officially released on April 13, 2005. On April 23, 2005, Acid2 was updated to fix a bug.^[15]

  The following is a list of releases noting significant builds of applications that passed the test.

  Date	Browser	Type	Notes
  April 27, 2005	Safari	non-public build[16]
  May 18, 2005	iCab	non-public build
  June 4, 2005	Konqueror	non-public build[17]
  June 6, 2005	iCab	public build	This version of iCab displays a scrollbar on the viewport. Although some state that a correctly rendered test should not have a scrollbar,[18] that feature is not part of the test, and merely a way to prevent the user from scrolling.
  June 7, 2005	WebKit	public build	The underpinnings of Safari were first made available as open source on June 7, 2005. A script was provided to run Safari against the updated WebKit, allowing it to pass the Acid2 test.
  October 31, 2005	Safari 2.0.2	official release	Included in Mac OS X 10.4.3. First official browser to pass test.
  November 29, 2005	Konqueror	official release[19]	Available with KDE 3.5. First Linux-compatible browser to pass the test, except for hiding the scrollbar.
  December 7, 2005	Prince 5.1	official release[20]	First non-web browser to pass test
  March 10, 2006	Opera	public weekly build[21]	First Windows-compatible browser to pass the test and also the first Linux-compatible browser to fully pass the test. A public beta was released on April 20, also successful.
  March 14, 2006	Shiira	official release
  March 28, 2006	Konqueror 3.5.2	official release[22]	Although previous releases passed, their compliance was questioned. This version did not show scrollbars.
  April 12, 2006	Mozilla Firefox	semi-public build[23]	The "reflow branch" nightly builds, whose code was branched from the Gecko 1.9/Firefox 3.0 trunk and was merged back into the trunk on December 8, 2006.
  May 24, 2006	Opera Mobile	non-public build[24]	First mobile browser to pass test
  June 20, 2006	Opera 9.0	official release[25]
  June 30, 2006	Obigo Browser	non-public build[26]	Second mobile browser to pass test
  August 17, 2006	iCab 3.0.3	official release	First public release that hides the scrollbars
  September 6, 2006	OmniWeb 5.5	official release
  September 7, 2006	Tkhtml Html Viewer 3 Alpha 10	public build	Alpha release
  December 8, 2006	Mozilla Firefox, Camino, SeaMonkey	public nightly build[27]	Firefox 3 reflow-refactoring branch lands on main Gecko trunk. Firefox/Camino/SeaMonkey trunk builds now pass Acid2, barring other regressions.
  April 11, 2007	Internet Channel	official release
  October 24, 2007	Prism 0.8	prototype[28]
  December 19, 2007	Internet Explorer 8 internal build	non-public build[29]	Microsoft stated that passing Acid2 is a goal for Internet Explorer 8
  March 5, 2008	Internet Explorer 8 Beta 1	public build[30]	Beta 1 release passes the official test

  See also

  • Acid1
  • Acid3
  • Comparison of layout engines

  References

  1. ^ Hyatt, Dave (2005-04-12). The Acid2 Test. Surfin' Safari. Retrieved on 2007-12-24.
  2. ^ CSS1 Test Suite: 5.5.26 clear. Retrieved on 2006-05-16.
  3. ^ W3C CSS Validator output. Retrieved on 2007-12-20.
  4. ^ Acid2 website. Retrieved on 2007-12-20.
  5. ^ ^{a b} Acid2: The Guided Tour. The Web Standards Project. Retrieved on 2007-12-24.
  6. ^ Molly Says: March 3rd, 2006 at 2:24 am. Microsoft IE7 Progress: Sneak Preview of MIX06 Release. Molly.com (1 March 2006). Retrieved on 2006-05-16.
  7. ^ Microsoft caves: ‘Super-standards’ mode to become IE 8 default. Retrieved on 2008-03-03.
  8. ^ Wilson, Chris (July 29 2005). Standards and CSS in IE. IEBlog. MSDN Blogs. Retrieved on 2008-03-11.
  9. ^ Geoff Duncan (2008-03-06). Internet Explorer 8 Beta Touts Standards. Digital Trends. Retrieved on 2008-03-09.
  10. ^ Phil Nachreiner (2008-03-05). Why Isn't IE8 Passing Acid2?. Micrososft. Retrieved on 2008-03-11.
  11. ^ Mozilla Gran Paradiso Alpha 2 Release Notes. mozilla.org (2007-06-09). Retrieved on 2008-03-07.
  12. ^ Altman, Tim (2006-07-19). Tim's Opera Bits v1.1. Tim's blog. Retrieved on 2007-11-15.
  13. ^ Acid2 and Opera 9 Clarifications: Yes, Opera 9 Passes the Test. Retrieved on 2006-07-22.
  14. ^ The Acid2 challenge to Microsoft. News.com (2005-03-16). Retrieved on 2008-01-12.
  15. ^ Hyatt, Dave (2005-04-23). Acid2: Version 1.1 Posted. Surfin' Safari. Retrieved on 2007-12-24.
  16. ^ Safari Passes the Acid2 Test (Updated). Retrieved on 2006-06-14.
  17. ^ carewolf (06/04/2005). Konqueror now passes Acid2. Retrieved on 2006-05-16.
  18. ^ Overflow:HTMLParser the 'Overflow' Property. W3C CSS working draft. World Wide Web Consortium. Retrieved on 2006-05-15.
  19. ^ K Desktop Environment 3.5 Released (November 29, 2005). Retrieved on 2006-05-16.
  20. ^ The Acid2 Test. Retrieved on 2006-05-16.
  21. ^ Acid2 - Rows 4 and 5 AKA Opera passes the Acid2 test!. Tim's blog (2006-03-10). Retrieved on 2006-05-16.
  22. ^ KDE 3.5.2 Release Announcement (March 28, 2006). Retrieved on 2006-05-16.
  23. ^ Braniecki, Zbigniew (2006-04-12). Meet Mr. Face. Stream of Thoughts. Retrieved on 2006-05-16.
  24. ^ Opera for Symbian passes Acid2. Retrieved on 2006-05-24.
  25. ^ Welcome to Opera 9.0. Retrieved on 2006-06-20.
  26. ^ Obigo Browser. Retrieved on 2006-06-30.
  27. ^ Mozilla Bug 289480. Retrieved on 2006-12-08.
  28. ^ Mozilla Labs blog. Retrieved on 2007-10-24.
  29. ^ Internet Explorer 8 and Acid2: A Milestone. Microsoft (2007-12-19). Retrieved on 2008-03-09.
  30. ^ Geoff Duncan (2008-03-06). Internet Explorer 8 Beta Touts Standards. Digital Trends. Retrieved on 2008-03-09.

  
  

  External links

  • Official Acid2 test
  • Acid2 test information
  • Official collection of Acid Tests
  • Acid2 press release
  • Acid2 test collection (wiki)
  • Article in CNET that proposed the Acid2 test
  • Safari first gold browser to pass Acid2
  • Mozilla Foundation's Acid2 tracking bug
  • Acid2 in major browsers - Shows Acid2 rendered in Safari, Prince, Opera, iCab, Konqueror, Netscape/Mozilla/Firefox, and Internet Explorer, showing their progressive improvements
  • Complete overview of Opera's Acid2 fixes
  • Press release from YesLogic: Prince 5.1 passes rigorous Acid2 test
  • Acid2 - the truth about Safari, iCab and Konqueror
  • The Box Acid Test (Acid1)

  
  

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