pytest: Change the channel persistence test to add inflight HTLCs

Now that we have HTLC persistence we'd also like to test it. This
kills the second node in the middle of an HTLC, it'll recover and
finish the flow.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

tests/test_lightningd.py

@@ -608,7 +608,7 @@ class LightningDTests(BaseLightningDTests):
         # (l1 will also collect its to-self payment.)
         l1.daemon.wait_for_log('sendrawtx exit 0')
         l1.daemon.wait_for_log('sendrawtx exit 0')
-        
+
         # We use 3 blocks for "reasonable depth"
         bitcoind.rpc.generate(3)
 
@@ -720,7 +720,7 @@ class LightningDTests(BaseLightningDTests):
 
         # Make sure l1 got l2's commitment to the HTLC, and sent to master.
         l1.daemon.wait_for_log('UPDATE WIRE_CHANNEL_GOT_COMMITSIG')
-        
+
         # Take our snapshot.
         tx = l1.rpc.dev_sign_last_tx(l2.info['id'])['tx']
 
@@ -734,7 +734,7 @@ class LightningDTests(BaseLightningDTests):
 
         l2.daemon.wait_for_log('peer_out WIRE_UPDATE_FULFILL_HTLC')
         l1.daemon.wait_for_log('peer_in WIRE_REVOKE_AND_ACK')
-        
+
         # Payment should now complete.
         t.result(timeout=10)
 
@@ -834,7 +834,7 @@ class LightningDTests(BaseLightningDTests):
 
         # This will fail at l2's end.
         t=self.pay(l1,l2,200000000,async=True)
-        
+
         l2.daemon.wait_for_log('dev_disconnect permfail')
         l2.daemon.wait_for_log('sendrawtx exit 0')
         bitcoind.rpc.generate(1)
@@ -857,7 +857,7 @@ class LightningDTests(BaseLightningDTests):
         bitcoind.rpc.generate(100)
         l1.daemon.wait_for_log('onchaind complete, forgetting peer')
         l2.daemon.wait_for_log('onchaind complete, forgetting peer')
-        
+
     def test_permfail_htlc_in(self):
         # Test case where we fail with unsettled incoming HTLC.
         disconnects = ['-WIRE_UPDATE_FULFILL_HTLC', 'permfail']
@@ -889,7 +889,7 @@ class LightningDTests(BaseLightningDTests):
         bitcoind.rpc.generate(6)
 
         l2.daemon.wait_for_log('sendrawtx exit 0')
-        
+
         t.cancel()
 
         # Now, 100 blocks it should be done.
@@ -898,7 +898,7 @@ class LightningDTests(BaseLightningDTests):
         assert not l2.daemon.is_in_log('onchaind complete, forgetting peer')
         bitcoind.rpc.generate(6)
         l2.daemon.wait_for_log('onchaind complete, forgetting peer')
-        
+
     def test_permfail_htlc_out(self):
         # Test case where we fail with unsettled outgoing HTLC.
         disconnects = ['+WIRE_REVOKE_AND_ACK', 'permfail']
@@ -1501,8 +1501,12 @@ class LightningDTests(BaseLightningDTests):
         assert outputs[2] == 10000000
 
     def test_channel_persistence(self):
-        # Start two nodes and open a channel (to remember)
-        l1, l2 = self.connect()
+        # Start two nodes and open a channel (to remember). l2 will
+        # mysteriously die while committing the first HTLC so we can
+        # check that HTLCs reloaded from the DB work.
+        l1 = self.node_factory.get_node()
+        l2 = self.node_factory.get_node(disconnect=['_WIRE_COMMITMENT_SIGNED'])
+        l1.rpc.connect('localhost', l2.info['port'], l2.info['id'])
 
         # Neither node should have a channel open, they are just connected
         for n in (l1, l2):
@@ -1517,13 +1521,18 @@ class LightningDTests(BaseLightningDTests):
         for n in (l1, l2):
             assert(n.db_query('SELECT COUNT(id) as count FROM channels;')[0]['count'] == 1)
 
-        # Perform a payment so we have something to restore
-        self.pay(l1, l2, 10000)
-        time.sleep(1)
-        assert l1.rpc.getpeers()['peers'][0]['msatoshi_to_us'] == 99990000
-        assert l2.rpc.getpeers()['peers'][0]['msatoshi_to_us'] == 10000
+        # Fire off a sendpay request, it'll get interrupted by a restart
+        fut = self.executor.submit(self.pay, l1, l2, 10000)
+        # Wait for it to be committed to, i.e., stored in the DB
+        l1.daemon.wait_for_log('peer_in WIRE_COMMITMENT_SIGNED')
+
         # Stop l2, l1 will reattempt to connect
-        l2.stop()
+        print("Killing l2 in mid HTLC")
+        l2.daemon.proc.terminate()
+
+        # Clear the disconnect and timer stop so we can proceed normally
+        l2.daemon.cmd_line = [e for e in l2.daemon.cmd_line if 'disconnect' not in e]
+        print(" ".join(l2.daemon.cmd_line + ['--dev-debugger=channeld']))
 
         # Wait for l1 to notice
         wait_for(lambda: not l1.rpc.getpeers()['peers'][0]['connected'])
@@ -1532,6 +1541,9 @@ class LightningDTests(BaseLightningDTests):
         l2.daemon.start()
         wait_for(lambda: len(l2.rpc.getpeers()['peers']) == 1)
 
+        # Wait for the restored HTLC to finish
+        wait_for(lambda: l1.rpc.getpeers()['peers'][0]['msatoshi_to_us'] == 99990000, interval=1)
+
         wait_for(lambda: len([p for p in l1.rpc.getpeers()['peers'] if p['connected']]), interval=1)
         wait_for(lambda: len([p for p in l2.rpc.getpeers()['peers'] if p['connected']]), interval=1)
 

tests/utils.py

@@ -235,7 +235,7 @@ class LightningD(TailableProc):
         ]
 
         self.cmd_line += ["--{}={}".format(k, v) for k, v in LIGHTNINGD_CONFIG.items()]
-        self.prefix = 'lightningd'
+        self.prefix = 'lightningd(%d)' % (port)
 
         if not os.path.exists(lightning_dir):
             os.makedirs(lightning_dir)