Allow immediate quit of sendpayment if no offers

In case Taker.initialize() fails for any reason such as no
liquidity, stallMonitor() will not wake up for 20*maker_timeout_sec;
so, in this change, IF the client schedule has length one, we
immediately figure the on_finished_callback with failure parameters
so that the reactor is stopped without waiting.
This change does not apply for the general multi-step schedule, as
that is principally for tumbler-style algos which are intended to
aggressively keep trying in case of any failure.

jmclient/jmclient/client_protocol.py

@@ -385,6 +385,11 @@ class JMTakerClientProtocol(JMClientProtocol):
         #True, self.cjamount, commitment, revelation, self.filtered_orderbook)
         if not retval[0]:
             jlog.info("Taker not continuing after receipt of orderbook")
+            if len(self.client.schedule) == 1:
+                #In single sendpayments, allow immediate quit.
+                #This could be an optional feature also for multi-entry schedules,
+                #but is not the functionality desired in general (tumbler).
+                self.client.on_finished_callback(False, True, 0.0)
             return {'accepted': True}
         amt, cmt, rev, foffers = retval[1:]
         d = self.callRemote(commands.JMFill,

jmclient/test/test_client_protocol.py

@@ -222,21 +222,24 @@ class TrialTestJMClientProto(unittest.TestCase):
             self.client = client
             self.addCleanup(self.client.transport.loseConnection)
         clientfactories = []
-        takers = [DummyTaker(None, None, callbacks=(None, None, dummy_taker_finished)) for _ in range(len(params))]
+        takers = [DummyTaker(
+            None, ["a", "b"], callbacks=(
+                None, None, dummy_taker_finished)) for _ in range(len(params))]
         for i, p in enumerate(params):
             takers[i].set_fail_init(p[0])
             takers[i].set_fail_utxos(p[1])
             takers[i].testflag = True
             if i != 0:
                 clientfactories.append(JMClientProtocolFactory(takers[i]))
-                clientconn = reactor.connectTCP("localhost", 27184, clientfactories[i])
+                clientconn = reactor.connectTCP("localhost", 27184,
+                                                clientfactories[i])
                 self.addCleanup(clientconn.disconnect)
             else:
                 clientfactories.append(DummyClientProtocolFactory(takers[i]))
                 clientfactory = clientfactories[0]
-                clientconn = reactor.connectTCP("localhost", 27184, clientfactories[0])
+                clientconn = reactor.connectTCP("localhost", 27184,
+                                                clientfactories[0])
                 self.addCleanup(clientconn.disconnect)
-        print("Got here")
 
     def test_waiter(self):
         print("test_main()")