This is a testharness.js-based test.
[FAIL] Requests with PUT method require CORS Preflight and succeed.
  assert_equals: expected "backgroundfetchsuccess" but got "backgroundfetchfail"
[FAIL] Requests with text/json content type require CORS Preflight and succeed.
  assert_equals: expected "backgroundfetchsuccess" but got "backgroundfetchfail"
Harness: the test ran to completion.