Filed by: malexandru [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer.html#?job_id=247698047&repo=mozilla-central
Full log: https://queue.taskcluster.net/v1/task/W2LFajFUTAmstZ3w8pFiMA/runs/1/artifacts/public/logs/live_backing.log

[task 2019-05-22T05:29:55.288Z] 05:29:55 INFO - TEST-START | /svg/types/elements/SVGGeometryElement-rect.svg
[task 2019-05-22T05:29:55.288Z] 05:29:55 INFO - Clearing pref dom.security.featurePolicy.enabled
[task 2019-05-22T05:29:55.304Z] 05:29:55 INFO - Closing window 2147483698
[task 2019-05-22T05:29:55.557Z] 05:29:55 INFO -
[task 2019-05-22T05:29:55.557Z] 05:29:55 INFO - TEST-UNEXPECTED-FAIL | /svg/types/elements/SVGGeometryElement-rect.svg | getTotalLength and getPointAtLength do not take pathLength into account - assert_equals: expected 600 but got 0
[task 2019-05-22T05:29:55.557Z] 05:29:55 INFO - @http://web-platform.test:8000/svg/types/elements/SVGGeometryElement-rect.svg:22:5
[task 2019-05-22T05:29:55.557Z] 05:29:55 INFO - Test.prototype.step@http://web-platform.test:8000/resources/testharness.js:1587:25
[task 2019-05-22T05:29:55.557Z] 05:29:55 INFO - test@http://web-platform.test:8000/resources/testharness.js:544:30
[task 2019-05-22T05:29:55.557Z] 05:29:55 INFO - @http://web-platform.test:8000/svg/types/elements/SVGGeometryElement-rect.svg:19:3
[task 2019-05-22T05:29:55.779Z] 05:29:55 INFO - .
[task 2019-05-22T05:29:55.779Z] 05:29:55 INFO - TEST-OK | /svg/types/elements/SVGGeometryElement-rect.svg | took 491ms
[task 2019-05-22T05:29:56.531Z] 05:29:56 INFO - Closing logging queue
[task 2019-05-22T05:29:56.531Z] 05:29:56 INFO - queue closed
[task 2019-05-22T05:29:56.550Z] 05:29:56 INFO - Setting up ssl
[task 2019-05-22T05:29:56.576Z] 05:29:56 INFO - certutil |
[task 2019-05-22T05:29:56.612Z] 05:29:56 INFO - certutil |
[task 2019-05-22T05:29:56.628Z] 05:29:56 INFO - certutil |
[task 2019-05-22T05:29:56.628Z] 05:29:56 INFO - Certificate Nickname Trust Attributes
[task 2019-05-22T05:29:56.628Z] 05:29:56 INFO - SSL,S/MIME,JAR/XPI
[task 2019-05-22T05:29:56.628Z] 05:29:56 INFO -
[task 2019-05-22T05:29:56.628Z] 05:29:56 INFO - web-platform-tests CT,,
[task 2019-05-22T05:29:56.628Z] 05:29:56 INFO -
[task 2019-05-22T05:29:58.403Z] 05:29:58 INFO - adb Granting important runtime permissions to org.mozilla.geckoview.test
[task 2019-05-22T05:29:59.659Z] 05:29:59 INFO - adb launch_application: am start -W -n org.mozilla.geckoview.test/org.mozilla.geckoview.test.TestRunnerActivity -a android.intent.action.MAIN --es env9 MOZ_PROCESS_LOG=/tmp/tmpOaip5Opidlog --es env8 MOZ_CRASHREPORTER_NO_REPORT=1 --es args "-no-remote -profile /sdcard/tests/profile --marionette about:blank" --es env3 STYLO_THREADS=4 --es env2 MOZ_HIDE_RESULTS_TABLE=1 --es env1 R_LOG_VERBOSE=1 --es env0 MOZ_CRASHREPORTER=1 --es env7 MOZ_DISABLE_NONLOCAL_CONNECTIONS=1 --es env6 R_LOG_DESTINATION=stderr --es env5 MOZ_CRASHREPORTER_SHUTDOWN=1 --es env4 MOZ_LOG=signaling:3,mtransport:4,DataChannel:4,jsep:4 --ez use_multiprocess True --es env10 R_LOG_LEVEL=6
[task 2019-05-22T05:30:01.399Z] 05:30:01 INFO - Starting runner
[task 2019-05-22T05:30:01.698Z] 05:30:01 INFO - TEST-START | /uievents/legacy-domevents-tests/submissions/Microsoft/converted/EventListener.dispatch.new.event.html

https://wiki.mozilla.org/Bug_Triage#Intermittent_Test_Failure_Cleanup