def testError(self):
        """ checks if a deferred errbacks """

        obj = Gobj()
        defe = OnEventDeferred(obj, "ok")
        defe.add_error_event(obj, "error")
        obj.emit("error")
        return defe.addCallbacks(self.fail, self.assertIsInstance, errbackArgs=(Failure,))
	def testError(self):
		""" checks if a deferred errbacks """

		obj = Gobj()
		defe = OnEventDeferred(obj, "ok")
		defe.add_error_event(obj, "error")
		obj.emit("error")
		return defe.addCallbacks(self.fail, 
			   self.assertIsInstance, 
			   errbackArgs=(Failure,))