rbf-test: confirm that rbf'd inflight is opened and closed as expected

We weren't testing that a non-tip inflight would get opened correctly.
Until now, that is.

tests/test_opening.py

@@ -865,6 +865,104 @@ def test_rbf_broadcast_close_inflights(node_factory, bitcoind, chainparams):
     assert inflights[1]['scratch_txid'] not in bitcoind.rpc.getrawmempool()
 
 
+@unittest.skipIf(TEST_NETWORK != 'regtest', 'elementsd doesnt yet support PSBT features we need')
+@pytest.mark.openchannel('v2')
+def test_rbf_non_last_mined(node_factory, bitcoind, chainparams):
+    """
+    What happens if a 'non-tip' RBF transaction is mined?
+    """
+    l1, l2 = node_factory.get_nodes(2,
+                                    opts={'allow_warning': True,
+                                          'may_reconnect': True})
+
+    l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+    amount = 2**24
+    chan_amount = 100000
+    bitcoind.rpc.sendtoaddress(l1.rpc.newaddr()['bech32'], amount / 10**8 + 0.01)
+    bitcoind.generate_block(1)
+    # Wait for it to arrive.
+    wait_for(lambda: len(l1.rpc.listfunds()['outputs']) > 0)
+
+    res = l1.rpc.fundchannel(l2.info['id'], chan_amount, feerate='7500perkw')
+    chan_id = res['channel_id']
+    vins = bitcoind.rpc.decoderawtransaction(res['tx'])['vin']
+    assert(only_one(vins))
+    prev_utxos = ["{}:{}".format(vins[0]['txid'], vins[0]['vout'])]
+
+    # Check that we're waiting for lockin
+    l1.daemon.wait_for_log(' to DUALOPEND_AWAITING_LOCKIN')
+    inflights = only_one(only_one(l1.rpc.listpeers()['peers'])['channels'])['inflight']
+    assert inflights[-1]['funding_txid'] in bitcoind.rpc.getrawmempool()
+
+    def run_retry():
+        startweight = 42 + 173
+        next_feerate = find_next_feerate(l1, l2)
+        initpsbt = l1.rpc.utxopsbt(chan_amount, next_feerate, startweight,
+                                   prev_utxos, reservedok=True,
+                                   min_witness_weight=110,
+                                   excess_as_change=True)
+
+        l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+        bump = l1.rpc.openchannel_bump(chan_id, chan_amount, initpsbt['psbt'])
+        update = l1.rpc.openchannel_update(chan_id, bump['psbt'])
+        assert update['commitments_secured']
+
+        return l1.rpc.signpsbt(update['psbt'])['signed_psbt']
+
+    # Make a second inflight
+    signed_psbt = run_retry()
+    l1.rpc.openchannel_signed(chan_id, signed_psbt)
+
+    # Make it such that l1 and l2 cannot broadcast transactions
+    # (mimics failing to reach the miner with replacement)
+    def censoring_sendrawtx(r):
+        return {'id': r['id'], 'result': {}}
+
+    l1.daemon.rpcproxy.mock_rpc('sendrawtransaction', censoring_sendrawtx)
+    l2.daemon.rpcproxy.mock_rpc('sendrawtransaction', censoring_sendrawtx)
+
+    # Make a 3rd inflight that won't make it into the mempool
+    signed_psbt = run_retry()
+    l1.rpc.openchannel_signed(chan_id, signed_psbt)
+
+    l1.daemon.rpcproxy.mock_rpc('sendrawtransaction', None)
+    l2.daemon.rpcproxy.mock_rpc('sendrawtransaction', None)
+
+    # We fetch out our inflights list
+    inflights = only_one(only_one(l1.rpc.listpeers()['peers'])['channels'])['inflight']
+
+    # l2 goes offline
+    l2.stop()
+
+    # The funding transaction gets mined (should be the 2nd inflight)
+    bitcoind.generate_block(6, wait_for_mempool=1)
+
+    # l2 comes back up
+    l2.start()
+
+    # everybody's got the right things now
+    l1.daemon.wait_for_log(r'to CHANNELD_NORMAL')
+    l2.daemon.wait_for_log(r'to CHANNELD_NORMAL')
+
+    channel = only_one(only_one(l1.rpc.listpeers()['peers'])['channels'])
+    assert channel['funding_txid'] == inflights[1]['funding_txid']
+    assert channel['scratch_txid'] == inflights[1]['scratch_txid']
+
+    # We delete inflights when the channel is in normal ops
+    assert 'inflights' not in channel
+
+    # l2 stops, again
+    l2.stop()
+
+    # l1 drops to chain.
+    l1.rpc.close(chan_id, 1)
+    l1.daemon.wait_for_log('Broadcasting txid {}'.format(channel['scratch_txid']))
+
+    # The funding transaction gets mined (should be the 2nd inflight)
+    bitcoind.generate_block(1, wait_for_mempool=1)
+    l1.daemon.wait_for_log(r'to ONCHAIN')
+
+
 @unittest.skipIf(TEST_NETWORK != 'regtest', 'elementsd doesnt yet support PSBT features we need')
 @pytest.mark.openchannel('v2')
 def test_funder_options(node_factory, bitcoind):