[iOS] Layout Test http/tests/preload/viewport/meta-viewport-link-headers.php is flaky

• Component: New Bugs
• Status: NEW ---

[Matt Lewis]

http/tests/preload/viewport/meta-viewport-link-headers.php is a flaky failure on iOS Simulator WK2 according to the flakiness dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=http%2Ftests%2Fpreload%2Fviewport%2Fmeta-viewport-link-headers.php

build:
https://build.webkit.org/results/Apple%20iOS%2011%20Simulator%20Release%20WK2%20(Tests)/r222986%20(371)/results.html
https://build.webkit.org/builders/Apple%20iOS%2011%20Simulator%20Release%20WK2%20(Tests)/builds/371

diff:

--- /Volumes/Data/slave/ios-simulator-11-release-tests-wk2/build/layout-test-results/http/tests/preload/viewport/meta-viewport-link-headers-expected.txt
+++ /Volumes/Data/slave/ios-simulator-11-release-tests-wk2/build/layout-test-results/http/tests/preload/viewport/meta-viewport-link-headers-actual.txt
@@ -1,3 +1,3 @@
 
-PASS Makes sure that Link headers support the media attribute and respond to <meta content=viewport> 
+FAIL Makes sure that Link headers support the media attribute and respond to <meta content=viewport> assert_true: The control element should be loaded expected true got false
 
first failure:
https://build.webkit.org/builders/Apple%20iOS%2011%20Simulator%20Release%20WK2%20(Tests)/builds/33

This test was thought to be fixed in https://bugs.webkit.org/show_bug.cgi?id=172518 but it looks like the fix did not work.

[Alexey Proskuryakov]

Yoav, would you be willing to take a look? Apparently the fix in bug 172518 wasn't sufficient.

[Alexey Proskuryakov]

I don't know if that's the cause of flakiness, but this test uses a common anti-pattern. 

The test starts before the document is completely loaded, so loading the image races with completing the document load. The assignment to img.src should happen no earlier than window.onload.

Also, instead of waiting for a second, the test can use shouldBecomeTrue from WebKit test harness (or an equivalent from W3C harness if it exists).

[youenn fablet]

Looking at the test, it might be missing a return after line 34.

As of the 1 second thing, since it is polling repetitively several times, I don't think there is an issue there.

[Alexey Proskuryakov]

It only polls for one second, and the load may not complete so quickly.

[Ryan Haddad]

Marked test as flaky in https://trac.webkit.org/changeset/224355/webkit