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background-size-022.html seems incorrect (Re: New tests submission for css3 background-clip/-origin/-size)

From: Gérard Talbot <css21testsuite@gtalbot.org>
Date: Sat, 13 Oct 2012 20:26:58 -0400
Message-ID: <6d7c082319ef87c917b42e48ca343c05.squirrel@ed-sh-cp3.entirelydigital.com>
To: "Zhang, Zhiqiang" <zhiqiang.zhang@intel.com>
Cc: "public-css-testsuite@w3.org" <public-css-testsuite@w3.org>, "Christensen, Kenneth" <kenneth.christensen@intel.com>, "Zhang, Haili" <haili.zhang@intel.com>, "Yu, Ling L" <ling.l.yu@intel.com>, "Yang, Lei A" <lei.a.yang@intel.com>
Le Sam 13 octobre 2012 5:09, Zhang, Zhiqiang a écrit :

> Review is appreciated:
> https://test.csswg.org/shepherd/search/testcase/author/intel/status/submitted/


http://test.csswg.org/source/contributors/intel/submitted/css3-background/background-size-022.html

<meta name="assert" content="Check if 'background-size' is '50% auto'
and 'background-origin is 'border-box' that it stretches the image so
that exactly two copies fit horizontally" />

The test passes only because, by default, background-repeat initial
value is set to 'repeat'.

http://www.w3.org/TR/css3-background/#the-background-repeat

So, any non-zero and non-negative percentage would make the test passed,
would lead to believe that the test passes.

Eg.

line 34: background-size: 1% auto;

or

line 34: background-size: 13% auto;

would still make the test pass anyway because background-repeat is
initially set to repeat.

"exactly two copies fit horizontally": that is true but because the
background-image is undifferentiated green and undifferentiable, this is
impossible to verify.

This test is not correct. And the text assert is also wrong.
'background-size: 50% auto'
will reduce the background-image to half the height of the border-box
which is the background area. In the test, this means 50% of border-box
area: 50% of (100px + 25px mult by 2 + 5px mult by 2) == 80px. It is
true that 2 copies of the background image fit horizontally but even if
it had been '13% auto', we still would not see any red anyway.

So the verb stretch is wrong: the background-image is horizontally
repeated and vertically repeated.

This is a weak test because it will not fail even if background-size is
not supported or even if the 'background-size: 50% auto' declaration is
not applied or rendered correctly.

Gérard
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Received on Sunday, 14 October 2012 00:27:30 GMT

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