1 Handling an error in the worker should suppress the page-level onerror handler.
3 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
7 Worker-level onerror handler triggered:
8 PASS errorEvent.message is "Uncaught ReferenceError: foo is not defined"
9 PASS stripURL(errorEvent.filename) is "[blob: URL]"
10 PASS errorEvent.lineno is 14
11 PASS errorEvent.colno is 9
12 PASS errorEvent.error is null
13 PASS successfullyParsed is true