Fix token network clean up

The token network state machine was not properly cleaning up the channel
state, if the channel state machine returns a new_state set to None the
token network must remove the NettingChannelState from it's map.

fix #1882

Author: hackaugusto

raiden/tests/unit/test_tokennetwork.py

@@ -4,7 +4,11 @@
 from raiden.constants import UINT64_MAX
 from raiden.tests.utils import factories
 from raiden.transfer import channel, token_network
-from raiden.transfer.state_change import ContractReceiveChannelNew
+from raiden.transfer.state_change import (
+    ContractReceiveChannelClosed,
+    ContractReceiveChannelNew,
+    ContractReceiveChannelSettled,
+)
 from raiden.transfer.state import TokenNetworkState
 
 
@@ -56,3 +60,58 @@ def test_contract_receive_channelnew_must_be_idempotent():
 
     channelmap_by_address = iteration.new_state.partneraddresses_to_channels
     assert channelmap_by_address[channel_state1.partner_state.address] == channel_state1, msg
+
+
+def test_channel_settle_must_properly_cleanup():
+    open_block_number = 10
+    pseudo_random_generator = random.Random()
+
+    token_network_id = factories.make_address()
+    token_id = factories.make_address()
+    token_network_state = TokenNetworkState(token_network_id, token_id)
+
+    amount = 30
+    our_balance = amount + 50
+    channel_state = factories.make_channel(our_balance=our_balance)
+
+    channel_new_state_change = ContractReceiveChannelNew(token_network_id, channel_state)
+
+    channel_new_iteration = token_network.state_transition(
+        token_network_state,
+        channel_new_state_change,
+        pseudo_random_generator,
+        open_block_number,
+    )
+
+    closed_block_number = open_block_number + 10
+    channel_close_state_change = ContractReceiveChannelClosed(
+        token_network_id,
+        channel_state.identifier,
+        channel_state.partner_state.address,
+        closed_block_number,
+    )
+
+    channel_closed_iteration = token_network.state_transition(
+        channel_new_iteration.new_state,
+        channel_close_state_change,
+        pseudo_random_generator,
+        closed_block_number,
+    )
+
+    settle_block_number = closed_block_number + channel_state.settle_timeout + 1
+    channel_settled_state_change = ContractReceiveChannelSettled(
+        token_network_id,
+        channel_state.identifier,
+        settle_block_number,
+    )
+
+    channel_settled_iteration = token_network.state_transition(
+        channel_closed_iteration.new_state,
+        channel_settled_state_change,
+        pseudo_random_generator,
+        closed_block_number,
+    )
+
+    token_network_state_after_settle = channel_settled_iteration.new_state
+    ids_to_channels = token_network_state_after_settle.channelidentifiers_to_channels
+    assert channel_state.identifier not in ids_to_channels

raiden/transfer/token_network.py

@@ -31,6 +31,12 @@ def subdispatch_to_channel_by_id(
             pseudo_random_generator,
             block_number,
         )
+
+        if result.new_state is None:
+            del ids_to_channels[state_change.channel_identifier]
+        else:
+            ids_to_channels[state_change.channel_identifier] = result.new_state
+
         events.extend(result.events)
 
     return TransitionResult(token_network_state, events)