Function asyncTest

packages/zone.js/test/browser/browser.spec.ts:3624–3637

(testFn: Function)

    xdescribe('unhandled promise rejection', () => {
      const AsyncTestZoneSpec = (Zone as any)['AsyncTestZoneSpec'];
      const asyncTest = function (testFn: Function) {
        return (done: Function) => {
          let asyncTestZone: Zone = Zone.current.fork(
            new AsyncTestZoneSpec(
              done,
              (error: Error) => {
                fail(error);
              },
              'asyncTest',
            ),
          );
          asyncTestZone.run(testFn);
        };
      };

      it(
        'should support window.addEventListener(unhandledrejection)',