pytest: test double-spending an opening tx input.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tests/test_connection.py

@@ -246,6 +246,39 @@ def test_second_channel(node_factory):
     l1.fundchannel(l3, 10**6)
 
 
+def test_channel_abandon(node_factory, bitcoind):
+    """Our open tx isn't mined, we doublespend it away"""
+    l1, l2 = node_factory.get_nodes(2)
+
+    SATS = 10**6
+
+    # Add some for fees
+    l1.fundwallet(SATS + 10000)
+    l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+    l1.rpc.fundchannel(l2.info['id'], SATS, feerate='1875perkw')
+
+    opening_utxo = only_one([o for o in l1.rpc.listfunds()['outputs'] if o['reserved']])
+    psbt = l1.rpc.utxopsbt(0, "253perkw", 0, [opening_utxo['txid'] + ':' + str(opening_utxo['output'])], reserve=False, reservedok=True)['psbt']
+
+    # Unreserve until it's considered unreserved.
+    count = 0
+    while only_one(l1.rpc.unreserveinputs(psbt)['reservations'])['reserved']:
+        count += 1
+    assert count == 1
+
+    # Now it's unreserved, we can doublespend it (as long as we exceed
+    # previous fee to RBF!).
+    withdraw = l1.rpc.withdraw(l1.rpc.newaddr()['bech32'], "all")
+
+    assert bitcoind.rpc.decoderawtransaction(withdraw['tx'])['vout'][0]['value'] > SATS / 10**8
+    bitcoind.generate_block(1, wait_for_mempool=withdraw['txid'])
+
+    # FIXME: lightningd should notice channel will never now open!
+    print(l1.rpc.listpeers())
+    assert (only_one(only_one(l1.rpc.listpeers()['peers'])['channels'])['state']
+            == 'CHANNELD_AWAITING_LOCKIN')
+
+
 @pytest.mark.developer
 @pytest.mark.openchannel('v1')
 @pytest.mark.openchannel('v2')