CONSOLE ERROR: Uncaught SomeError The test passes if 'window.onerror' is invoked with unsanitized information on a script loaded with a 'crossorigin' attribute, but loads from same-origin and without valid CORS headers. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS /SomeError/.test(msg) is true PASS url is "http://127.0.0.1:8000/security/resources/cors-script.php?fail=true&cors=false" PASS line is 1 PASS column is 1 PASS window.errorObject is not null PASS successfullyParsed is true TEST COMPLETE