Filed by: hskupin [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer.html#?job_id=315344494&repo=mozilla-central
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/JJZ2ylQOTdWHitC9O23jng/runs/0/artifacts/public/logs/live_backing.log

There are still failures like that for some tests like `/fetch/corb/script-resource-with-json-parser-breaker.tentative.sub.html`. In those cases the `DOMContentLoaded` event gets fired with a readyState of `complete`. As such we seem to return too early from the navigation:

https://searchfox.org/mozilla-central/rev/eb9d5c97927aea75f0c8e38bbc5b5d288099e687/testing/web-platform/tests/tools/wptrunner/wptrunner/executors/executormarionette.py#839

Based on that the script `testharnessreport.js` hasn't been loaded / run yet, and the method `window.__wptrunner_process_next_event()` isn't available yet.```

Here when running with trace logs enabled:

0:11.21 pid:32508 1599768932172	Marionette	DEBUG	2 -> [0,12,"WebDriver:Navigate",{"url":"http://web-platform.test:8000/fetch/corb/script-resource-with-json-parser-breaker.tentative.sub.html"}]
 0:11.21 pid:32508 1599768932174	Marionette	TRACE	Using browsing context 36
 0:11.21 pid:32508 1599768932179	Marionette	TRACE	[36] Received DOM event beforeunload for about:blank
 0:11.22 pid:32508 1599768932190	Marionette	TRACE	[36] Received DOM event pagehide for about:blank
 0:11.22 pid:32508 1599768932194	Marionette	TRACE	[36] Received DOM event beforeunload for http://web-platform.test:8000/fetch/corb/script-resource-with-json-parser-breaker.tentative.sub.html
 0:11.22 pid:32508 1599768932194	Marionette	TRACE	[36] Received DOM event DOMContentLoaded for http://web-platform.test:8000/fetch/corb/script-resource-with-json-parser-breaker.tentative.sub.html
 0:11.22 pid:32508 1599768932195	Marionette	TRACE	[36] readystate: complete

My patch on bug 1612831 seems to help here, or even fixes that. Lets re-check when it has been landed.

Removing the intermittent-failure keyword to focus on getting the following failure line classified.

I can no longer see this failure for wpt1 since my patch has been merged to mozilla-central.