Failure in VclTextTest::testSimpleText due to antialiasing (Linux)

[Ilmari Lauhakangas]

On 4.12.2021 10.40, Ilmari Lauhakangas wrote:
> A mentee is running into a test failure on Ubuntu 21.10 (output below). 
> The image produced by the test has a coloured fringe. Luboš commented on 
> it:
> 
> "Colors in AA mean that's AA for LCD.
> There's special code to handle that, I suppose the test should 
> temporarily disable that for the text rendering."
> 
> How can we achieve this?
> 
> Ilmari
> 
> [CUT] vcl_svm_test
> [_RUN_____] (anonymous namespace)::CanvasBitmapTest::runTest
> (anonymous namespace)::CanvasBitmapTest::runTest finished in: 144ms
> [_RUN_____] VclComplexTextTest::testArabic
> VclComplexTextTest::testArabic finished in: 107ms
> [_RUN_____] VclComplexTextTest::testKashida
> VclComplexTextTest::testKashida finished in: 1ms
> [_RUN_____] VclComplexTextTest::testTdf95650
> VclComplexTextTest::testTdf95650 finished in: 5ms
> [_RUN_____] VclComplexTextTest::testCaching
> VclComplexTextTest::testCaching finished in: 8ms
> [_RUN_____] VclTextTest::testSimpleText
> /home/akshit16/libreoffice/vcl/qa/cppunit/text.cxx:251:VclTextTest::testSimpleText
> double equality assertion failed
> - Expected: 28
> - Actual  : -1
> - Delta   : 2
> 
> VclTextTest::testSimpleText finished in: 27ms
> [_RUN_____] VclTextTest::testVerticalText
> VclTextTest::testVerticalText finished in: 0ms
> [_RUN_____] VclTextTest::testTextLayoutCache
> VclTextTest::testTextLayoutCache finished in: 0ms
> [_RUN_____] VclTextTest::testImplLayoutRuns_AddPos
> VclTextTest::testImplLayoutRuns_AddPos finished in: 0ms
> [_RUN_____] VclTextTest::testImplLayoutRuns_AddRuns
> VclTextTest::testImplLayoutRuns_AddRuns finished in: 0ms
> [_RUN_____] VclTextTest::testImplLayoutRuns_PosIsInRun
> VclTextTest::testImplLayoutRuns_PosIsInRun finished in: 0ms
> [_RUN_____] VclTextTest::testImplLayoutRuns_PosIsInAnyRun
> VclTextTest::testImplLayoutRuns_PosIsInAnyRun finished in: 0ms
> [_RUN_____] VclTextTest::testImplLayoutArgsBiDiStrong
> VclTextTest::testImplLayoutArgsBiDiStrong finished in: 0ms
> [_RUN_____] VclTextTest::testImplLayoutArgsBiDiRtl
> VclTextTest::testImplLayoutArgsBiDiRtl finished in: 0ms
> [_RUN_____] VclTextTest::testImplLayoutArgsRightAlign
> VclTextTest::testImplLayoutArgsRightAlign finished in: 0ms
> [_RUN_____] 
> VclTextTest::testImplLayoutArgs_PrepareFallback_precalculatedglyphs
> VclTextTest::testImplLayoutArgs_PrepareFallback_precalculatedglyphs 
> finished in: 10ms
> text.cxx:251:Assertion
> Test name: VclTextTest::testSimpleText
> double equality assertion failed
> - Expected: 28
> - Actual  : -1
> - Delta   : 2

Thanks to Stephan Bergmann for fixing this!
https://git.libreoffice.org/core/+/933519505aee0e91ca99af0ed860e4a0f148f922

Ilmari