testUnauthorizedLoading() {
    const mm = getModuleManager({'m': [], 'n': [], 'o': ['n']});
    mm.setLoader(createUnsuccessfulLoader(mm, 401));

    // Callback checks for an unauthorized error
    let firedLoadFailed = false;
    mm.registerCallback(
        ModuleManager.CallbackType.ERROR, (callbackType, id, cause) => {
          assertEquals(
              'Failure cause was not as expected',
              ModuleLoadFailure.Type.UNAUTHORIZED, cause.type);
          firedLoadFailed = true;
        });
    mm.execOnLoad('o', () => {});
    assertTrue('module "o" should be loading', mm.isModuleLoading('o'));
    assertTrue('module "n" should be loading', mm.isModuleLoading('n'));
    clock.tick(5);
    assertTrue(
        'should have called unauthorized module callback', firedLoadFailed);
    assertFalse('module "o" should not be loaded', mm.isModuleLoaded('o'));
    assertFalse('module "o" should not be loading', mm.isModuleLoading('o'));
    assertFalse('module "n" should not be loaded', mm.isModuleLoaded('n'));
    assertFalse('module "n" should not be loading', mm.isModuleLoading('n'));
  }
Test unauthorized errors while loading modules.
     @suppress {missingProperties} suppression added to enable type checking