From a74cc99e6a6cf82fbe319ccff17bcf6f7c76f3b5 Mon Sep 17 00:00:00 2001
From: Brian Warner <warner@lothar.com>
Date: Fri, 5 Jul 2019 23:16:25 -0700
Subject: [PATCH] dilate: test sending data while the connection is offline

---
 src/wormhole/_dilation/manager.py     |  6 ++
 src/wormhole/test/dilate/test_full.py | 85 +++++++++++++++++++++++++++
 2 files changed, 91 insertions(+)

diff --git a/src/wormhole/_dilation/manager.py b/src/wormhole/_dilation/manager.py
index 574c7b2..581a721 100644
--- a/src/wormhole/_dilation/manager.py
+++ b/src/wormhole/_dilation/manager.py
@@ -116,6 +116,7 @@ class Manager(object):
         self._made_first_connection = False
         self._first_connected = OneShotObserver(self._eventual_queue)
         self._stopped = OneShotObserver(self._eventual_queue)
+        self._debug_stall_connector = False
 
         self._next_dilation_phase = 0
 
@@ -382,6 +383,11 @@ class Manager(object):
                                     self._timing,
                                     self._my_side,  # needed for relay handshake
                                     self._my_role)
+        if self._debug_stall_connector:
+            # unit tests use this hook to send messages while we know we
+            # don't have a connection
+            self._eventual_queue.eventually(self._debug_stall_connector, self._connector)
+            return
         self._connector.start()
 
     @m.output()
diff --git a/src/wormhole/test/dilate/test_full.py b/src/wormhole/test/dilate/test_full.py
index 50fd3a2..ee089c7 100644
--- a/src/wormhole/test/dilate/test_full.py
+++ b/src/wormhole/test/dilate/test_full.py
@@ -6,6 +6,7 @@ from twisted.internet.protocol import Protocol, Factory
 from twisted.trial import unittest
 
 from ..common import ServerBase, poll_until
+from ..._interfaces import IDilationConnector
 from ...eventual import EventualQueue
 from ..._dilation._noise import NoiseConnection
 
@@ -178,3 +179,87 @@ class Reconnect(ServerBase, unittest.TestCase):
 
         yield w1.close()
         yield w2.close()
+
+    @inlineCallbacks
+    def test_data_while_offline(self):
+        eq = EventualQueue(reactor)
+        w1 = wormhole.create(APPID, self.relayurl, reactor, _enable_dilate=True)
+        w2 = wormhole.create(APPID, self.relayurl, reactor, _enable_dilate=True)
+        w1.allocate_code()
+        code = yield w1.get_code()
+        w2.set_code(code)
+        yield doBoth(w1.get_verifier(), w2.get_verifier())
+
+        eps1_d = w1.dilate()
+        eps2_d = w2.dilate()
+        (eps1, eps2) = yield doBoth(eps1_d, eps2_d)
+        (control_ep1, connect_ep1, listen_ep1) = eps1
+        (control_ep2, connect_ep2, listen_ep2) = eps2
+
+        f1 = ReconF(eq); f2 = ReconF(eq)
+        d1 = control_ep1.connect(f1); d2 = control_ep2.connect(f2)
+        yield d1
+        yield d2
+
+        protocols = {}
+        def p_connected(p, index):
+            protocols[index] = p
+            msg = "hello from %s\n" % index
+            p.transport.write(msg.encode("ascii"))
+        f1.deferreds["connectionMade"].addCallback(p_connected, 1)
+        f2.deferreds["connectionMade"].addCallback(p_connected, 2)
+
+        data1 = yield f1.deferreds["dataReceived"]
+        data2 = yield f2.deferreds["dataReceived"]
+        self.assertEqual(data1, b"hello from 2\n")
+        self.assertEqual(data2, b"hello from 1\n")
+        # the ACKs are now in flight and may not arrive before we kill the
+        # connection
+
+        f1.resetDeferred("connectionMade")
+        f2.resetDeferred("connectionMade")
+        d1 = f1.resetDeferred("dataReceived")
+        d2 = f2.resetDeferred("dataReceived")
+
+        # switch off connections
+        assert w1._boss._D._manager._debug_stall_connector == False
+        cd1 = Deferred(); cd2 = Deferred()
+        w1._boss._D._manager._debug_stall_connector = cd1.callback
+        w2._boss._D._manager._debug_stall_connector = cd2.callback
+
+        # now we reach inside and drop the connection
+        sc = protocols[1].transport
+        orig_connection = sc._manager._connection
+        orig_connection.disconnect()
+
+        c1 = yield cd1
+        c2 = yield cd2
+        assert IDilationConnector.providedBy(c1)
+        assert IDilationConnector.providedBy(c2)
+        assert c1 is not orig_connection
+        w1._boss._D._manager._debug_stall_connector = False
+        w2._boss._D._manager._debug_stall_connector = False
+
+        # now write some data while the connection is definitely offline
+        protocols[1].transport.write(b"more 1->2\n")
+        protocols[2].transport.write(b"more 2->1\n")
+
+        # allow the connections to proceed
+        c1.start()
+        c2.start()
+
+        # and wait for the data to arrive
+        data2 = yield d2
+        self.assertEqual(data2, b"more 1->2\n")
+        data1 = yield d1
+        self.assertEqual(data1, b"more 2->1\n")
+
+        # the application-visible Protocol should not observe the
+        # interruption
+        self.assertNoResult(f1.deferreds["connectionMade"])
+        self.assertNoResult(f2.deferreds["connectionMade"])
+        self.assertNoResult(f1.deferreds["connectionLost"])
+        self.assertNoResult(f2.deferreds["connectionLost"])
+
+        yield w1.close()
+        yield w2.close()