'The corresponding method of the provider of the interface is called in
a thread using the threadpool specified to ``auto_threaded``.'

def test_called_in_threadpool(self):

    before = self.threadpool.calls
    self.successResultOf(self.async_spy.method(self.a, self.b, self.c))
    after = self.threadpool.calls
    self.assertEqual((before, after), (0, 1))
