Automated test failures in current Firefox stable

[jeffposnick]

The automated tests in the build process are currently failing Firefox stable, due to

the cross-origin fetch handler is used when the path and origin matches
‣

Error: NetworkError when attempting to fetch resource.

return window._controlledPromise.then(function() {
  return window.fetch('https://matching.domain/path/to/customFetch').then(function(response) {
    assert.equal(response.status, 410, 'Custom response status doesn\'t match');
  });
});

I can reproduce the failure locally with the stable Firefox release, but everything works fine in Firefox Nightly:

I am chalking this up to an incomplete Firefox service worker implementation that was later properly implemented. (The failing test covers a fairly obscure use case.)

I'm just leaving this issue open to track that as the Firefox stable release is bumped the test starts passing again.