This test is a flaky test both for WPE and GTK: https://results.webkit.org/?suite=layout-tests&test=fast%2Frepaint%2FbackgroundSizeRepaint.html&platform=GTK&platform=WPE It's possible to reproduce the flaky failure by running the test at least 2 times: ``` $ Tools/Scripts/run-webkit-tests --no-show-results --no-new-test-results --no-sample-on-timeout --results-directory layout-test-results --debug-rwt-logging --no-retry-failures --release --gtk --force --repeat 2 fast/repaint/backgroundSizeRepaint.html ``` When the test fails, the results show that the actual image is not fully completed (compared to the expected image). Introducing a delay of at least 1000 ms before calling `notifyDone`, makes the test always pass (no flakies): ```diff diff --git a/LayoutTests/fast/repaint/backgroundSizeRepaint.html b/LayoutTests/fast/repaint/backgroundSizeRepaint.html index 5c241cb6c6c8..853b42d0e3ad 100644 --- a/LayoutTests/fast/repaint/backgroundSizeRepaint.html +++ b/LayoutTests/fast/repaint/backgroundSizeRepaint.html @@ -12,8 +12,10 @@ { document.getElementById('a').style.height = '40px'; document.getElementById('b').style.height = '60px'; - if (window.testRunner) - testRunner.notifyDone(); + setTimeout(() => { + if (window.testRunner) + testRunner.notifyDone(); + }, 1000); } </script> </head> ``` It doesn't seem other ports need a delay.