Refactor channel states:

- persisted states are saved
 - state transitions are checked
 - transient states are stored in channel.peer_state
 - new channel states: 'PREOPENING', 'FUNDED' and 'REDEEMED'
 - upgrade storage to version 21

electrum/tests/regtest/regtest.sh

@@ -90,6 +90,10 @@ if [[ $1 == "init" ]]; then
     new_blocks 1
 fi
 
+if [[ $1 == "new_block" ]]; then
+    new_blocks 1
+fi
+
 # start daemons. Bob is started first because he is listening
 if [[ $1 == "start" ]]; then
     $bob daemon -d

electrum/tests/test_lnchannel.py

@@ -34,6 +34,7 @@ from electrum.lnutil import SENT, LOCAL, REMOTE, RECEIVED
 from electrum.lnutil import FeeUpdate
 from electrum.ecc import sig_string_from_der_sig
 from electrum.logging import console_stderr_handler
+from electrum.lnchannel import channel_states
 
 from . import ElectrumTestCase
 
@@ -94,6 +95,7 @@ def create_channel_state(funding_txid, funding_index, funding_sat, is_initiator,
             ),
             "node_id":other_node_id,
             'onion_keys': {},
+            'state': 'PREOPENING',
     }
 
 def bip32(sequence):
@@ -136,8 +138,8 @@ def create_test_channels(feerate=6000, local=None, remote=None):
     alice.hm.log[LOCAL]['ctn'] = 0
     bob.hm.log[LOCAL]['ctn'] = 0
 
-    alice.set_state('OPEN')
-    bob.set_state('OPEN')
+    alice._state = channel_states.OPEN
+    bob._state = channel_states.OPEN
 
     a_out = alice.get_latest_commitment(LOCAL).outputs()
     b_out = bob.get_next_commitment(REMOTE).outputs()

electrum/tests/test_lnpeer.py

@@ -16,6 +16,7 @@ from electrum.lnpeer import Peer
 from electrum.lnutil import LNPeerAddr, Keypair, privkey_to_pubkey
 from electrum.lnutil import LightningPeerConnectionClosed, RemoteMisbehaving
 from electrum.lnutil import PaymentFailure, LnLocalFeatures
+from electrum.lnchannel import channel_states
 from electrum.lnrouter import LNPathFinder
 from electrum.channel_db import ChannelDB
 from electrum.lnworker import LNWallet, NoPathFound
@@ -202,9 +203,9 @@ class TestPeer(ElectrumTestCase):
         w1.peer = p1
         w2.peer = p2
         # mark_open won't work if state is already OPEN.
-        # so set it to OPENING
-        self.alice_channel.set_state("OPENING")
-        self.bob_channel.set_state("OPENING")
+        # so set it to FUNDED
+        self.alice_channel._state = channel_states.FUNDED
+        self.bob_channel._state = channel_states.FUNDED
         # this populates the channel graph:
         p1.mark_open(self.alice_channel)
         p2.mark_open(self.bob_channel)