@gen_test
    def test_future_traceback(self):
        @return_future
        @gen.engine
        def f(callback):
            yield gen.Task(self.io_loop.add_callback)
            try:
                1 / 0
            except ZeroDivisionError:
                self.expected_frame = traceback.extract_tb(
                    sys.exc_info()[2], limit=1)[0]
                raise
        try:
            yield f()
            self.fail("didn't get expected exception")
        except ZeroDivisionError:
            tb = traceback.extract_tb(sys.exc_info()[2])
            self.assertIn(self.expected_frame, tb)

# The following series of classes demonstrate and test various styles
# of use, with and without generators and futures.
dataset/ETHPy150Open cloudaice/simple-data/misc/virtenv/lib/python2.7/site-packages/tornado/test/concurrent_test.py/ReturnFutureTest.test_future_traceback/original