core-lightning/tests/test_askrene.py

from fixtures import *  # noqa: F401,F403
from hashlib import sha256
from pyln.client import RpcError
from pyln.testing.utils import SLOW_MACHINE
from utils import (
    only_one, first_scid, GenChannel, generate_gossip_store,
    sync_blockheight, wait_for, TEST_NETWORK, TIMEOUT
)
import os
import pytest
import subprocess
import time
import tempfile


def direction(src, dst):
    """BOLT 7 direction: 0 means from lesser encoded id"""
    if src < dst:
        return 0
    return 1


def test_reserve(node_factory):
    """Test reserving channels"""
    l1, l2, l3 = node_factory.line_graph(3, wait_for_announce=True)

    assert l1.rpc.askrene_listreservations() == {'reservations': []}
    scid12 = first_scid(l1, l2)
    scid23 = first_scid(l2, l3)
    scid12dir = f"{scid12}/{direction(l1.info['id'], l2.info['id'])}"
    scid23dir = f"{scid23}/{direction(l2.info['id'], l3.info['id'])}"

    initial_prob = l1.rpc.getroutes(source=l1.info['id'],
                                    destination=l3.info['id'],
                                    amount_msat=1000000,
                                    layers=[],
                                    maxfee_msat=100000,
                                    final_cltv=0)['probability_ppm']

    # Reserve 1000 sats on path.  This should reduce probability!
    l1.rpc.askrene_reserve(path=[{'short_channel_id_dir': scid12dir,
                                  'amount_msat': 1000_000},
                                 {'short_channel_id_dir': scid23dir,
                                  'amount_msat': 1000_001}])
    listres = l1.rpc.askrene_listreservations()['reservations']
    if listres[0]['short_channel_id_dir'] == scid12dir:
        assert listres[0]['amount_msat'] == 1000_000
        assert listres[1]['short_channel_id_dir'] == scid23dir
        assert listres[1]['amount_msat'] == 1000_001
    else:
        assert listres[0]['short_channel_id_dir'] == scid23dir
        assert listres[0]['amount_msat'] == 1000_001
        assert listres[1]['short_channel_id_dir'] == scid12dir
        assert listres[1]['amount_msat'] == 1000_000
    assert len(listres) == 2

    assert l1.rpc.getroutes(source=l1.info['id'],
                            destination=l3.info['id'],
                            amount_msat=1000000,
                            layers=[],
                            maxfee_msat=100000,
                            final_cltv=0)['probability_ppm'] < initial_prob

    # Now reserve so much there's nothing left.
    l1.rpc.askrene_reserve(path=[{'short_channel_id_dir': scid12dir,
                                  'amount_msat': 1000_000_000_000},
                                 {'short_channel_id_dir': scid23dir,
                                  'amount_msat': 1000_000_000_000}])

    # Keep it consistent: the below will mention a time if >= 1 seconds old,
    # which might happen without the sleep on slow machines.
    time.sleep(2)

    # Reservations can be in either order.
    with pytest.raises(RpcError, match=rf'We could not find a usable set of paths.  The shortest path is {scid12}->{scid23}, but {scid12dir} already reserved 10000000*msat by command ".*" \([0-9]* seconds ago\), 10000000*msat by command ".*" \([0-9]* seconds ago\)'):
        l1.rpc.getroutes(source=l1.info['id'],
                         destination=l3.info['id'],
                         amount_msat=1000000,
                         layers=[],
                         maxfee_msat=100000,
                         final_cltv=0)['probability_ppm']

    # Can't remove wrong amounts: that's user error
    with pytest.raises(RpcError, match="Unknown reservation"):
        l1.rpc.askrene_unreserve(path=[{'short_channel_id_dir': scid12dir,
                                        'amount_msat': 1000_001},
                                       {'short_channel_id_dir': scid23dir,
                                        'amount_msat': 1000_000}])

    # Remove, it's all ok.
    l1.rpc.askrene_unreserve(path=[{'short_channel_id_dir': scid12dir,
                                    'amount_msat': 1000_000},
                                   {'short_channel_id_dir': scid23dir,
                                    'amount_msat': 1000_001}])
    l1.rpc.askrene_unreserve(path=[{'short_channel_id_dir': scid12dir,
                                    'amount_msat': 1000_000_000_000},
                                   {'short_channel_id_dir': scid23dir,
                                    'amount_msat': 1000_000_000_000}])
    assert l1.rpc.askrene_listreservations() == {'reservations': []}
    assert l1.rpc.getroutes(source=l1.info['id'],
                            destination=l3.info['id'],
                            amount_msat=1000000,
                            layers=[],
                            maxfee_msat=100000,
                            final_cltv=0)['probability_ppm'] == initial_prob

    # Reserving in reverse makes no difference!
    scid12rev = f"{first_scid(l1, l2)}/{direction(l2.info['id'], l1.info['id'])}"
    scid23rev = f"{first_scid(l2, l3)}/{direction(l3.info['id'], l2.info['id'])}"
    l1.rpc.askrene_reserve(path=[{'short_channel_id_dir': scid12rev,
                                  'amount_msat': 1000_000_000_000},
                                 {'short_channel_id_dir': scid23rev,
                                  'amount_msat': 1000_000_000_000}])
    assert l1.rpc.getroutes(source=l1.info['id'],
                            destination=l3.info['id'],
                            amount_msat=1000000,
                            layers=[],
                            maxfee_msat=100000,
                            final_cltv=0)['probability_ppm'] == initial_prob


def test_layers(node_factory):
    """Test manipulating information in layers"""
    # remove xpay, since it creates a layer!
    l1, l2, l3 = node_factory.line_graph(3, wait_for_announce=True,
                                         opts={'disable-plugin': 'cln-xpay'})

    assert l2.rpc.askrene_listlayers() == {'layers': []}
    with pytest.raises(RpcError, match="Unknown layer"):
        l2.rpc.askrene_listlayers('test_layers')

    expect = {'layer': 'test_layers',
              'persistent': False,
              'disabled_nodes': [],
              'created_channels': [],
              'channel_updates': [],
              'constraints': [],
              'biases': []}
    l2.rpc.askrene_create_layer('test_layers')
    l2.rpc.askrene_disable_node('test_layers', l1.info['id'])
    expect['disabled_nodes'].append(l1.info['id'])
    assert l2.rpc.askrene_listlayers('test_layers') == {'layers': [expect]}
    assert l2.rpc.askrene_listlayers() == {'layers': [expect]}
    with pytest.raises(RpcError, match="Unknown layer"):
        l2.rpc.askrene_listlayers('test_layers2')

    l2.rpc.askrene_update_channel('test_layers', "0x0x1/0", False)
    expect['channel_updates'].append({'short_channel_id_dir': "0x0x1/0",
                                      'enabled': False})
    assert l2.rpc.askrene_listlayers('test_layers') == {'layers': [expect]}
    with pytest.raises(RpcError, match="Layer already exists"):
        l2.rpc.askrene_create_layer('test_layers')

    # Tell it l3 connects to l1!
    l2.rpc.askrene_create_channel('test_layers',
                                  l3.info['id'],
                                  l1.info['id'],
                                  '0x0x1',
                                  '1000000sat')
    # src/dst gets turned into BOLT 7 order
    expect['created_channels'].append({'source': l1.info['id'],
                                       'destination': l3.info['id'],
                                       'short_channel_id': '0x0x1',
                                       'capacity_msat': 1000000000})
    assert l2.rpc.askrene_listlayers('test_layers') == {'layers': [expect]}

    # And give details.
    l2.rpc.askrene_update_channel(layer='test_layers',
                                  short_channel_id_dir='0x0x1/0',
                                  htlc_minimum_msat=100,
                                  htlc_maximum_msat=900000000,
                                  fee_base_msat=1,
                                  fee_proportional_millionths=2,
                                  cltv_expiry_delta=18)
    # This is *still* disabled, since we disabled it above!
    expect['channel_updates'] = [{'short_channel_id_dir': '0x0x1/0',
                                  'enabled': False,
                                  'htlc_minimum_msat': 100,
                                  'htlc_maximum_msat': 900000000,
                                  'fee_base_msat': 1,
                                  'fee_proportional_millionths': 2,
                                  'cltv_expiry_delta': 18}]
    assert l2.rpc.askrene_listlayers('test_layers') == {'layers': [expect]}

    # Now enable (and change another value for good measure!
    l2.rpc.askrene_update_channel(layer='test_layers',
                                  short_channel_id_dir='0x0x1/0',
                                  enabled=True,
                                  cltv_expiry_delta=19)
    expect['channel_updates'] = [{'short_channel_id_dir': '0x0x1/0',
                                  'enabled': True,
                                  'htlc_minimum_msat': 100,
                                  'htlc_maximum_msat': 900000000,
                                  'fee_base_msat': 1,
                                  'fee_proportional_millionths': 2,
                                  'cltv_expiry_delta': 19}]
    assert l2.rpc.askrene_listlayers('test_layers') == {'layers': [expect]}

    # We can tell it about made up channels...
    first_timestamp = int(time.time())
    l2.rpc.askrene_inform_channel('test_layers',
                                  '0x0x1/1',
                                  100000,
                                  'unconstrained')
    last_timestamp = int(time.time()) + 1
    expect['constraints'].append({'short_channel_id_dir': '0x0x1/1',
                                  'minimum_msat': 100000})
    # Check timestamp first.
    listlayers = l2.rpc.askrene_listlayers('test_layers')
    ts1 = only_one(only_one(listlayers['layers'])['constraints'])['timestamp']
    assert first_timestamp <= ts1 <= last_timestamp
    expect['constraints'][0]['timestamp'] = ts1
    assert listlayers == {'layers': [expect]}

    # Make sure timestamps differ!
    time.sleep(2)

    # We can tell it about existing channels...
    scid12 = first_scid(l1, l2)
    first_timestamp = int(time.time())
    scid12dir = f"{scid12}/{direction(l2.info['id'], l1.info['id'])}"
    l2.rpc.askrene_inform_channel(layer='test_layers',
                                  short_channel_id_dir=scid12dir,
                                  amount_msat=12341235,
                                  inform='constrained')
    last_timestamp = int(time.time()) + 1
    expect['constraints'].append({'short_channel_id_dir': scid12dir,
                                  'timestamp': first_timestamp,
                                  'maximum_msat': 12341234})
    # Check timestamp first.
    listlayers = l2.rpc.askrene_listlayers('test_layers')
    ts2 = only_one([c['timestamp'] for c in only_one(listlayers['layers'])['constraints'] if c['short_channel_id_dir'] == scid12dir])
    assert first_timestamp <= ts2 <= last_timestamp
    expect['constraints'][1]['timestamp'] = ts2

    # Could be either order!
    actual = expect.copy()
    if only_one(listlayers['layers'])['constraints'][0]['short_channel_id_dir'] == scid12dir:
        actual['constraints'] = [expect['constraints'][1], expect['constraints'][0]]
    assert listlayers == {'layers': [actual]}

    # Now test aging: ts1 does nothing.
    assert l2.rpc.askrene_age('test_layers', ts1) == {'layer': 'test_layers', 'num_removed': 0}
    listlayers = l2.rpc.askrene_listlayers('test_layers')
    assert listlayers == {'layers': [actual]}

    # ts1+1 removes first inform
    assert l2.rpc.askrene_age('test_layers', ts1 + 1) == {'layer': 'test_layers', 'num_removed': 1}
    del expect['constraints'][0]
    listlayers = l2.rpc.askrene_listlayers('test_layers')
    assert listlayers == {'layers': [expect]}

    # ts2+1 removes other.
    assert l2.rpc.askrene_age('test_layers', ts2 + 1) == {'layer': 'test_layers', 'num_removed': 1}
    del expect['constraints'][0]
    listlayers = l2.rpc.askrene_listlayers('test_layers')
    assert listlayers == {'layers': [expect]}

    with pytest.raises(RpcError, match="Unknown layer"):
        l2.rpc.askrene_remove_layer('test_layers_unknown')

    # Add biases.
    l2.rpc.askrene_bias_channel('test_layers', '1x1x1/1', 1)
    expect['biases'] = [{'short_channel_id_dir': '1x1x1/1', 'bias': 1}]
    listlayers = l2.rpc.askrene_listlayers('test_layers')
    assert listlayers == {'layers': [expect]}

    # Works with description.
    l2.rpc.askrene_bias_channel('test_layers', '1x1x1/1', -5, "bigger bias")
    expect['biases'] = [{'short_channel_id_dir': '1x1x1/1', 'bias': -5, 'description': "bigger bias"}]
    listlayers = l2.rpc.askrene_listlayers('test_layers')
    assert listlayers == {'layers': [expect]}

    with pytest.raises(RpcError, match="bias: should be a number between -100 and 100"):
        l2.rpc.askrene_bias_channel('test_layers', '1x1x1/1', -101)

    with pytest.raises(RpcError, match="bias: should be a number between -100 and 100"):
        l2.rpc.askrene_bias_channel('test_layers', '1x1x1/1', 101, "bigger bias")

    # We can remove them.
    l2.rpc.askrene_bias_channel('test_layers', '1x1x1/1', 0)
    expect['biases'] = []
    listlayers = l2.rpc.askrene_listlayers('test_layers')
    assert listlayers == {'layers': [expect]}

    assert l2.rpc.askrene_remove_layer('test_layers') == {}
    assert l2.rpc.askrene_listlayers() == {'layers': []}

    # This layer is not persistent.
    l2.rpc.askrene_create_layer('test_layers')
    l2.restart()
    assert l2.rpc.askrene_listlayers() == {'layers': []}


def test_layer_persistence(node_factory):
    """Test persistence of layers across restart"""
    l1, l2 = node_factory.line_graph(2, wait_for_announce=True,
                                     opts={'disable-plugin': 'cln-xpay'})

    assert l1.rpc.askrene_listlayers() == {'layers': []}
    with pytest.raises(RpcError, match="Unknown layer"):
        l1.rpc.askrene_listlayers('test_layer_persistence')

    l1.rpc.askrene_create_layer(layer='test_layer_persistence', persistent=True)
    expect = {'layer': 'test_layer_persistence',
              'persistent': True,
              'disabled_nodes': [],
              'created_channels': [],
              'channel_updates': [],
              'constraints': [],
              'biases': []}
    assert l1.rpc.askrene_listlayers('test_layer_persistence') == {'layers': [expect]}

    # Restart, (empty layer) should still be there.
    l1.restart()

    assert l1.rpc.askrene_listlayers('test_layer_persistence') == {'layers': [expect]}

    # Re-creation of persistent layer is a noop.
    l1.rpc.askrene_create_layer(layer='test_layer_persistence', persistent=True)

    # Populate it.
    l1.rpc.askrene_disable_node('test_layer_persistence', l1.info['id'])
    l1.rpc.askrene_update_channel('test_layer_persistence', "0x0x1/0", False)
    l1.rpc.askrene_create_channel('test_layer_persistence',
                                  l2.info['id'],
                                  l1.info['id'],
                                  '0x0x1',
                                  '1000000sat')
    l1.rpc.askrene_update_channel(layer='test_layer_persistence',
                                  short_channel_id_dir='0x0x1/0',
                                  htlc_minimum_msat=100,
                                  htlc_maximum_msat=900000000,
                                  fee_base_msat=1,
                                  fee_proportional_millionths=2,
                                  cltv_expiry_delta=18)
    l1.rpc.askrene_update_channel(layer='test_layer_persistence',
                                  short_channel_id_dir='0x0x1/0',
                                  enabled=True,
                                  cltv_expiry_delta=19)
    l1.rpc.askrene_inform_channel('test_layer_persistence',
                                  '0x0x1/1',
                                  100000,
                                  'unconstrained')
    scid12 = first_scid(l1, l2)
    scid12dir = f"{scid12}/{direction(l1.info['id'], l2.info['id'])}"
    l1.rpc.askrene_inform_channel(layer='test_layer_persistence',
                                  short_channel_id_dir=scid12dir,
                                  amount_msat=12341235,
                                  inform='constrained')

    expect = l1.rpc.askrene_listlayers('test_layer_persistence')

    l1.restart()
    assert l1.rpc.askrene_listlayers('test_layer_persistence') == expect

    # Aging will cause a rewrite.
    assert l1.rpc.askrene_age('test_layer_persistence', 1) == {'layer': 'test_layer_persistence', 'num_removed': 0}
    assert l1.rpc.askrene_listlayers('test_layer_persistence') == expect
    l1.restart()
    assert l1.rpc.askrene_listlayers('test_layer_persistence') == expect

    # Delete layer, it won't reappear.
    assert l1.rpc.askrene_remove_layer('test_layer_persistence') == {}
    assert l1.rpc.askrene_listlayers() == {'layers': []}
    l1.restart()
    assert l1.rpc.askrene_listlayers() == {'layers': []}


def check_route_as_expected(routes, paths):
    """Make sure all fields in paths are match those in routes"""
    def dict_subset_eq(a, b):
        """Is every key in B is the same in A?"""
        return all(a.get(key) == b[key] for key in b)

    for path in paths:
        found = False
        for i in range(len(routes)):
            route = routes[i]
            if len(route['path']) != len(path):
                continue
            if all(dict_subset_eq(route['path'][i], path[i]) for i in range(len(path))):
                del routes[i]
                found = True
                break
        if not found:
            raise ValueError("Could not find path {} in paths {}".format(path, routes))

    if routes != []:
        raise ValueError("Did not expect paths {}".format(routes))


def check_getroute_paths(node,
                         source,
                         destination,
                         amount_msat,
                         paths,
                         layers=[],
                         maxfee_msat=1000,
                         final_cltv=99):
    """Check that routes are as expected in result"""
    getroutes = node.rpc.getroutes(source=source,
                                   destination=destination,
                                   amount_msat=amount_msat,
                                   layers=layers,
                                   maxfee_msat=maxfee_msat,
                                   final_cltv=final_cltv)

    assert getroutes['probability_ppm'] <= 1000000
    # Total delivered should be amount we told it to send.
    assert amount_msat == sum([r['amount_msat'] for r in getroutes['routes']])

    check_route_as_expected(getroutes['routes'], paths)


def test_getroutes(node_factory):
    """Test getroutes call"""
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1, forward=GenChannel.Half(propfee=10000)),
                                             GenChannel(0, 2, capacity_sats=9000),
                                             GenChannel(1, 3, forward=GenChannel.Half(propfee=20000)),
                                             GenChannel(0, 2, capacity_sats=10000),
                                             GenChannel(2, 4, forward=GenChannel.Half(delay=2000))])

    # Set up l1 with this as the gossip_store
    l1 = node_factory.get_node(gossip_store_file=gsfile.name)

    # Too much should give a decent explanation.
    with pytest.raises(RpcError, match=r"We could not find a usable set of paths\.  The shortest path is 0x1x0, but 0x1x0/1 isn't big enough to carry 1000000001msat\."):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[1],
                         amount_msat=1000000001,
                         layers=[],
                         maxfee_msat=100000000,
                         final_cltv=99)

    # This should tell us source doesn't have enough.
    with pytest.raises(RpcError, match=r"We could not find a usable set of paths\.  Total source capacity is only 1019000000msat \(in 3 channels\)\."):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[1],
                         amount_msat=2000000001,
                         layers=[],
                         maxfee_msat=20000000,
                         final_cltv=99)

    # This should tell us dest doesn't have enough.
    with pytest.raises(RpcError, match=r"We could not find a usable set of paths\.  Total destination capacity is only 1000000000msat \(in 1 channels\)\."):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[4],
                         amount_msat=1000000001,
                         layers=[],
                         maxfee_msat=30000000,
                         final_cltv=99)

    # Disabling channels makes getroutes fail
    l1.rpc.askrene_create_layer('chans_disabled')
    l1.rpc.askrene_update_channel(layer="chans_disabled",
                                  short_channel_id_dir='0x1x0/1',
                                  enabled=False)
    with pytest.raises(RpcError, match=r"We could not find a usable set of paths\.  The shortest path is 0x1x0, but 0x1x0/1 marked disabled by layer chans_disabled\."):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[1],
                         amount_msat=1000,
                         layers=["chans_disabled"],
                         maxfee_msat=1000,
                         final_cltv=99)

    # Start easy
    assert l1.rpc.getroutes(source=nodemap[0],
                            destination=nodemap[1],
                            amount_msat=1000,
                            layers=[],
                            maxfee_msat=1000,
                            final_cltv=99) == {'probability_ppm': 999999,
                                               'routes': [{'probability_ppm': 999999,
                                                           'final_cltv': 99,
                                                           'amount_msat': 1000,
                                                           'path': [{'short_channel_id_dir': '0x1x0/1',
                                                                     'next_node_id': nodemap[1],
                                                                     'amount_msat': 1010,
                                                                     'delay': 99 + 6}]}]}
    # Two hop, still easy.
    assert l1.rpc.getroutes(source=nodemap[0],
                            destination=nodemap[3],
                            amount_msat=100000,
                            layers=[],
                            maxfee_msat=5000,
                            final_cltv=99) == {'probability_ppm': 999798,
                                               'routes': [{'probability_ppm': 999798,
                                                           'final_cltv': 99,
                                                           'amount_msat': 100000,
                                                           'path': [{'short_channel_id_dir': '0x1x0/1',
                                                                     'next_node_id': nodemap[1],
                                                                     'amount_msat': 103020,
                                                                     'delay': 99 + 6 + 6},
                                                                    {'short_channel_id_dir': '1x3x2/1',
                                                                     'next_node_id': nodemap[3],
                                                                     'amount_msat': 102000,
                                                                     'delay': 99 + 6}
                                                                    ]}]}

    # Too expensive
    with pytest.raises(RpcError, match="Could not find route without excessive cost"):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[3],
                         amount_msat=100000,
                         layers=[],
                         maxfee_msat=100,
                         final_cltv=99)

    # Too much delay (if final delay too great!)
    l1.rpc.getroutes(source=nodemap[0],
                     destination=nodemap[4],
                     amount_msat=100000,
                     layers=[],
                     maxfee_msat=100,
                     final_cltv=6)
    with pytest.raises(RpcError, match="Could not find route without excessive delays"):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[4],
                         amount_msat=100000,
                         layers=[],
                         maxfee_msat=100,
                         final_cltv=99)

    # Two choices, but for <= 1000 sats we choose the larger.
    assert l1.rpc.getroutes(source=nodemap[0],
                            destination=nodemap[2],
                            amount_msat=1000000,
                            layers=[],
                            maxfee_msat=5000,
                            final_cltv=99) == {'probability_ppm': 900000,
                                               'routes': [{'probability_ppm': 900000,
                                                           'final_cltv': 99,
                                                           'amount_msat': 1000000,
                                                           'path': [{'short_channel_id_dir': '0x2x3/1',
                                                                     'next_node_id': nodemap[2],
                                                                     'amount_msat': 1000001,
                                                                     'delay': 99 + 6}]}]}

    # For 10000 sats, we will split.
    check_getroute_paths(l1,
                         nodemap[0],
                         nodemap[2],
                         10000000,
                         [[{'short_channel_id_dir': '0x2x1/1',
                            'next_node_id': nodemap[2],
                            'amount_msat': 4500004,
                            'delay': 99 + 6}],
                          [{'short_channel_id_dir': '0x2x3/1',
                            'next_node_id': nodemap[2],
                            'amount_msat': 5500005,
                            'delay': 99 + 6}]])


def test_getroutes_fee_fallback(node_factory):
    """Test getroutes call takes into account fees, if excessive"""

    # 0 -> 1 -> 3: high capacity, high fee (1%)
    # 0 -> 2 -> 3: low capacity, low fee.
    # (We disable reverse, since it breaks median calc!)
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1,
                                                        capacity_sats=20000,
                                                        forward=GenChannel.Half(propfee=10000),
                                                        reverse=GenChannel.Half(enabled=False)),
                                             GenChannel(0, 2,
                                                        capacity_sats=10000,
                                                        reverse=GenChannel.Half(enabled=False)),
                                             GenChannel(1, 3,
                                                        capacity_sats=20000,
                                                        forward=GenChannel.Half(propfee=10000),
                                                        reverse=GenChannel.Half(enabled=False)),
                                             GenChannel(2, 3,
                                                        capacity_sats=10000,
                                                        reverse=GenChannel.Half(enabled=False))])
    # Set up l1 with this as the gossip_store
    l1 = node_factory.get_node(gossip_store_file=gsfile.name)

    # Don't hit maxfee?  Go easy path.
    check_getroute_paths(l1,
                         nodemap[0],
                         nodemap[3],
                         10000,
                         maxfee_msat=201,
                         paths=[[{'short_channel_id_dir': '0x1x0/1'},
                                 {'short_channel_id_dir': '1x3x2/1'}]])

    # maxfee exceeded?  lower prob path.
    check_getroute_paths(l1,
                         nodemap[0],
                         nodemap[3],
                         10000,
                         maxfee_msat=200,
                         paths=[[{'short_channel_id_dir': '0x2x1/1'},
                                 {'short_channel_id_dir': '2x3x3/0'}]])


def test_getroutes_auto_sourcefree(node_factory):
    """Test getroutes call with auto.sourcefree layer"""
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1, forward=GenChannel.Half(propfee=10000)),
                                             GenChannel(0, 2, capacity_sats=9000),
                                             GenChannel(1, 3, forward=GenChannel.Half(propfee=20000)),
                                             GenChannel(0, 2, capacity_sats=10000),
                                             GenChannel(2, 4, forward=GenChannel.Half(delay=2000))])

    # Set up l1 with this as the gossip_store
    l1 = node_factory.get_node(gossip_store_file=gsfile.name)

    # Without sourcefree:
    assert l1.rpc.getroutes(source=nodemap[0],
                            destination=nodemap[1],
                            amount_msat=1000,
                            layers=[],
                            maxfee_msat=1000,
                            final_cltv=99) == {'probability_ppm': 999999,
                                               'routes': [{'probability_ppm': 999999,
                                                           'final_cltv': 99,
                                                           'amount_msat': 1000,
                                                           'path': [{'short_channel_id_dir': '0x1x0/1',
                                                                     'next_node_id': nodemap[1],
                                                                     'amount_msat': 1010,
                                                                     'delay': 105}]}]}

    # Start easy
    assert l1.rpc.getroutes(source=nodemap[0],
                            destination=nodemap[1],
                            amount_msat=1000,
                            layers=['auto.sourcefree'],
                            maxfee_msat=1000,
                            final_cltv=99) == {'probability_ppm': 999999,
                                               'routes': [{'probability_ppm': 999999,
                                                           'final_cltv': 99,
                                                           'amount_msat': 1000,
                                                           'path': [{'short_channel_id_dir': '0x1x0/1',
                                                                     'next_node_id': nodemap[1],
                                                                     'amount_msat': 1000,
                                                                     'delay': 99}]}]}
    # Two hop, still easy.
    assert l1.rpc.getroutes(source=nodemap[0],
                            destination=nodemap[3],
                            amount_msat=100000,
                            layers=['auto.sourcefree'],
                            maxfee_msat=5000,
                            final_cltv=99) == {'probability_ppm': 999798,
                                               'routes': [{'probability_ppm': 999798,
                                                           'final_cltv': 99,
                                                           'amount_msat': 100000,
                                                           'path': [{'short_channel_id_dir': '0x1x0/1',
                                                                     'next_node_id': nodemap[1],
                                                                     'amount_msat': 102000,
                                                                     'delay': 99 + 6},
                                                                    {'short_channel_id_dir': '1x3x2/1',
                                                                     'next_node_id': nodemap[3],
                                                                     'amount_msat': 102000,
                                                                     'delay': 99 + 6}
                                                                    ]}]}

    # Too expensive
    with pytest.raises(RpcError, match="Could not find route without excessive cost"):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[3],
                         amount_msat=100000,
                         layers=[],
                         maxfee_msat=100,
                         final_cltv=99)

    # Too much delay (if final delay too great!)
    l1.rpc.getroutes(source=nodemap[0],
                     destination=nodemap[4],
                     amount_msat=100000,
                     layers=[],
                     maxfee_msat=100,
                     final_cltv=6)
    with pytest.raises(RpcError, match="Could not find route without excessive delays"):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[4],
                         amount_msat=100000,
                         layers=[],
                         maxfee_msat=100,
                         final_cltv=99)


def test_getroutes_auto_localchans(node_factory):
    """Test getroutes call with auto.localchans layer"""
    l1 = node_factory.get_node()
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1, forward=GenChannel.Half(propfee=10000)),
                                             GenChannel(1, 2, forward=GenChannel.Half(propfee=10000))],
                                            nodemap={0: l1.info['id']})

    # We get bad signature warnings, since our gossip is made up!
    l2 = node_factory.get_node(allow_warning=True, gossip_store_file=gsfile.name)

    # Now l2 believes l1 has an entire network behind it.
    scid12, _ = l2.fundchannel(l1, 10**6, announce_channel=False)

    # Cannot find a route unless we use local hints.
    with pytest.raises(RpcError, match="Unknown source node {}".format(l2.info['id'])):
        l2.rpc.getroutes(source=l2.info['id'],
                         destination=nodemap[2],
                         amount_msat=100000,
                         layers=[],
                         maxfee_msat=100000,
                         final_cltv=99)

    # This should work
    scid21dir = f"{scid12}/{direction(l2.info['id'], l1.info['id'])}"
    check_getroute_paths(l2,
                         l2.info['id'],
                         nodemap[2],
                         100000,
                         maxfee_msat=100000,
                         layers=['auto.localchans'],
                         paths=[[{'short_channel_id_dir': scid21dir, 'amount_msat': 102012, 'delay': 99 + 6 + 6 + 6},
                                 {'short_channel_id_dir': '0x1x0/0', 'amount_msat': 102010, 'delay': 99 + 6 + 6},
                                 {'short_channel_id_dir': '1x2x1/1', 'amount_msat': 101000, 'delay': 99 + 6}]])

    # This should get self-discount correct
    check_getroute_paths(l2,
                         l2.info['id'],
                         nodemap[2],
                         100000,
                         maxfee_msat=100000,
                         layers=['auto.localchans', 'auto.sourcefree'],
                         paths=[[{'short_channel_id_dir': scid21dir, 'amount_msat': 102010, 'delay': 99 + 6 + 6},
                                 {'short_channel_id_dir': '0x1x0/0', 'amount_msat': 102010, 'delay': 99 + 6 + 6},
                                 {'short_channel_id_dir': '1x2x1/1', 'amount_msat': 101000, 'delay': 99 + 6}]])


def test_fees_dont_exceed_constraints(node_factory):
    msat = 100000000
    max_msat = int(msat * 0.45)
    # 0 has to use two paths (1 and 2) to reach 3.  But we tell it 0->1 has limited capacity.
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1, capacity_sats=msat // 1000, forward=GenChannel.Half(propfee=10000)),
                                             GenChannel(0, 2, capacity_sats=msat // 1000, forward=GenChannel.Half(propfee=10000)),
                                             GenChannel(1, 3, capacity_sats=msat // 1000, forward=GenChannel.Half(propfee=10000)),
                                             GenChannel(2, 3, capacity_sats=msat // 1000, forward=GenChannel.Half(propfee=10000))])

    # Set up l1 with this as the gossip_store
    l1 = node_factory.get_node(gossip_store_file=gsfile.name)

    chan = only_one([c for c in l1.rpc.listchannels(source=nodemap[0])['channels'] if c['destination'] == nodemap[1]])
    l1.rpc.askrene_create_layer('test_layers')
    l1.rpc.askrene_inform_channel(layer='test_layers',
                                  short_channel_id_dir=f"{chan['short_channel_id']}/{chan['direction']}",
                                  amount_msat=max_msat + 1,
                                  inform='constrained')

    routes = l1.rpc.getroutes(source=nodemap[0],
                              destination=nodemap[3],
                              amount_msat=msat,
                              layers=['test_layers'],
                              maxfee_msat=msat,
                              final_cltv=99)['routes']
    assert len(routes) == 2
    for hop in routes[0]['path'] + routes[1]['path']:
        if hop['short_channel_id_dir'] == f"{chan['short_channel_id']}/{chan['direction']}":
            amount = hop['amount_msat']
    assert amount <= max_msat


def test_sourcefree_on_mods(node_factory, bitcoind):
    """auto.sourcefree should also apply to layer-created channels"""
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1, forward=GenChannel.Half(propfee=10000)),
                                             GenChannel(0, 2, forward=GenChannel.Half(propfee=10000))])

    l1 = node_factory.get_node(gossip_store_file=gsfile.name)

    # Add a local channel from 0->l1 (we just needed a nodeid).
    l1.rpc.askrene_create_layer('test_layers')
    l1.rpc.askrene_create_channel('test_layers',
                                  nodemap[0],
                                  l1.info['id'],
                                  '0x3x3',
                                  '1000000sat')
    l1.rpc.askrene_update_channel(layer='test_layers',
                                  short_channel_id_dir=f'0x3x3/{direction(nodemap[0], l1.info["id"])}',
                                  enabled=True,
                                  htlc_minimum_msat=100,
                                  htlc_maximum_msat='900000sat',
                                  fee_base_msat=1000,
                                  fee_proportional_millionths=2000,
                                  cltv_expiry_delta=18)
    routes = l1.rpc.getroutes(source=nodemap[0],
                              destination=l1.info['id'],
                              amount_msat=1000000,
                              layers=['test_layers', 'auto.sourcefree'],
                              maxfee_msat=100000,
                              final_cltv=99)['routes']
    # Expect no fee.
    check_route_as_expected(routes, [[{'short_channel_id_dir': '0x3x3/1',
                                       'amount_msat': 1000000, 'delay': 99}]])

    # NOT if we specify layers in the other order!
    routes = l1.rpc.getroutes(source=nodemap[0],
                              destination=l1.info['id'],
                              amount_msat=1000000,
                              layers=['auto.sourcefree', 'test_layers'],
                              maxfee_msat=100000,
                              final_cltv=99)['routes']
    # Expect no fee.
    check_route_as_expected(routes, [[{'short_channel_id_dir': '0x3x3/1',
                                       'amount_msat': 1003000, 'delay': 117}]])


def test_live_spendable(node_factory, bitcoind):
    """Test we don't exceed spendable limits on a real network on nodes"""
    l1, l2, l3 = node_factory.get_nodes(3)
    l1.fundwallet(10_000_000)
    l2.fundwallet(10_000_000)
    l1.rpc.connect(l2.info['id'], 'localhost', port=l2.port)
    l2.rpc.connect(l3.info['id'], 'localhost', port=l3.port)

    capacities = (100_000, 100_000, 200_000, 300_000, 400_000)
    for capacity in capacities:
        l1.rpc.fundchannel(l2.info["id"], capacity, mindepth=1)
        l2.rpc.fundchannel(l3.info["id"], capacity, mindepth=1)

        bitcoind.generate_block(1, wait_for_mempool=2)
        sync_blockheight(bitcoind, [l1, l2])

    bitcoind.generate_block(5)
    wait_for(lambda: len(l1.rpc.listchannels()["channels"]) == 2 * 2 * len(capacities))

    routes = l1.rpc.getroutes(
        source=l1.info["id"],
        destination=l3.info["id"],
        amount_msat=800_000_001,
        layers=["auto.localchans", "auto.sourcefree"],
        maxfee_msat=50_000_000,
        final_cltv=10,
    )

    # Don't exceed spendable_msat
    maxes = {}
    for chan in l1.rpc.listpeerchannels()["channels"]:
        maxes["{}/{}".format(chan["short_channel_id"], chan["direction"])] = chan[
            "spendable_msat"
        ]

    path_total = {}
    num_htlcs = {}
    for r in routes["routes"]:
        key = r["path"][0]["short_channel_id_dir"]
        path_total[key] = path_total.get(key, 0) + r["path"][0]["amount_msat"]
        num_htlcs[key] = num_htlcs.get(key, 0) + 1

    # Take into account 645000msat (3750 feerate x 172 weight) per-HTLC reduction in capacity.
    for k in path_total.keys():
        if k in maxes:
            maxes[k] -= (3750 * 172) * (num_htlcs[k] - 1)

    exceeded = {}
    for scidd in maxes.keys():
        if scidd in path_total:
            if path_total[scidd] > maxes[scidd]:
                exceeded[scidd] = f"Path total {path_total[scidd]} > spendable {maxes[scidd]}"

    assert exceeded == {}

    # No duplicate paths!
    for i in range(0, len(routes["routes"])):
        path_i = [p['short_channel_id_dir'] for p in routes["routes"][i]['path']]
        for j in range(i + 1, len(routes["routes"])):
            path_j = [p['short_channel_id_dir'] for p in routes["routes"][j]['path']]
            assert path_i != path_j

    # Must deliver exact amount.
    assert sum(r['amount_msat'] for r in routes["routes"]) == 800_000_001


def test_limits_fake_gossmap(node_factory, bitcoind):
    """Like test_live_spendable, but using a generated gossmap not real nodes"""
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1, capacity_sats=100_000),
                                             GenChannel(0, 1, capacity_sats=100_000),
                                             GenChannel(0, 1, capacity_sats=200_000),
                                             GenChannel(0, 1, capacity_sats=300_000),
                                             GenChannel(0, 1, capacity_sats=400_000),
                                             GenChannel(1, 2, capacity_sats=100_000),
                                             GenChannel(1, 2, capacity_sats=100_000),
                                             GenChannel(1, 2, capacity_sats=200_000),
                                             GenChannel(1, 2, capacity_sats=300_000),
                                             GenChannel(1, 2, capacity_sats=400_000)])
    l1 = node_factory.get_node(gossip_store_file=gsfile.name)

    # Create a layer like auto.localchans would from "spendable"
    spendable = {'0x1x0/1': 87718000,
                 '0x1x1/1': 87718000,
                 '0x1x2/1': 186718000,
                 '0x1x3/1': 285718000,
                 '0x1x4/1': 384718000}

    # Sanity check that these exist!
    for scidd in spendable:
        assert scidd in [f"{c['short_channel_id']}/{c['direction']}" for c in l1.rpc.listchannels(source=nodemap[0])['channels']]

    # We tell it we could get through amount, but not amount + 1.
    # This makes min == max, just like we do for auto.localchans spendable.
    l1.rpc.askrene_create_layer('localchans')
    for scidd, amount in spendable.items():
        l1.rpc.askrene_inform_channel(layer='localchans',
                                      short_channel_id_dir=scidd,
                                      amount_msat=amount,
                                      inform='unconstrained')
        l1.rpc.askrene_inform_channel(layer='localchans',
                                      short_channel_id_dir=scidd,
                                      amount_msat=amount + 1,
                                      inform='constrained')

    routes = l1.rpc.getroutes(
        source=nodemap[0],
        destination=nodemap[2],
        amount_msat=800_000_001,
        layers=["localchans", "auto.sourcefree"],
        maxfee_msat=50_000_000,
        final_cltv=10,
    )

    path_total = {}
    for r in routes["routes"]:
        key = r["path"][0]["short_channel_id_dir"]
        path_total[key] = path_total.get(key, 0) + r["path"][0]["amount_msat"]

    exceeded = {}
    for scidd in spendable.keys():
        if scidd in path_total:
            if path_total[scidd] > spendable[scidd]:
                exceeded[scidd] = f"Path total {path_total[scidd]} > spendable {spendable[scidd]}"

    assert exceeded == {}

    # No duplicate paths!
    for i in range(0, len(routes["routes"])):
        path_i = [p['short_channel_id_dir'] for p in routes["routes"][i]['path']]
        for j in range(i + 1, len(routes["routes"])):
            path_j = [p['short_channel_id_dir'] for p in routes["routes"][j]['path']]
            assert path_i != path_j

    # Must deliver exact amount.
    assert sum(r['amount_msat'] for r in routes["routes"]) == 800_000_001


def test_max_htlc(node_factory, bitcoind):
    """A route which looks good isn't actually, because of max htlc limits"""
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1, capacity_sats=500_000,
                                                        forward=GenChannel.Half(htlc_max=1_000_000)),
                                             GenChannel(0, 1, capacity_sats=20_000)])
    l1 = node_factory.get_node(gossip_store_file=gsfile.name)

    routes = l1.rpc.getroutes(source=nodemap[0],
                              destination=nodemap[1],
                              amount_msat=20_000_000,
                              layers=[],
                              maxfee_msat=20_000_000,
                              final_cltv=10)

    check_route_as_expected(routes['routes'],
                            [[{'short_channel_id_dir': '0x1x0/1', 'amount_msat': 1_000_001, 'delay': 10 + 6}],
                             [{'short_channel_id_dir': '0x1x1/1', 'amount_msat': 19_000_019, 'delay': 10 + 6}]])

    # If we can't use channel 2, we fail.
    l1.rpc.askrene_create_layer('removechan2')
    l1.rpc.askrene_inform_channel(layer='removechan2',
                                  short_channel_id_dir='0x1x1/1',
                                  amount_msat=1,
                                  inform='constrained')

    with pytest.raises(RpcError, match="We could not find a usable set of paths.  The shortest path is 0x1x0, but 0x1x0/1 exceeds htlc_maximum_msat ~1000448msat"):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[1],
                         amount_msat=20_000_000,
                         layers=['removechan2'],
                         maxfee_msat=20_000_000,
                         final_cltv=10)


def test_min_htlc(node_factory, bitcoind):
    """A route which looks good isn't actually, because of min htlc limits"""
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1, capacity_sats=500_000,
                                                        forward=GenChannel.Half(htlc_min=2_000)),
                                             GenChannel(0, 1, capacity_sats=20_000)])
    l1 = node_factory.get_node(gossip_store_file=gsfile.name)

    with pytest.raises(RpcError, match="Amount 1000msat below minimum 2000msat across 0x1x0/1"):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[1],
                         amount_msat=1000,
                         layers=[],
                         maxfee_msat=20_000_000,
                         final_cltv=10)


def test_min_htlc_after_excess(node_factory, bitcoind):
    gsfile, nodemap = generate_gossip_store([GenChannel(0, 1, capacity_sats=500_000,
                                                        forward=GenChannel.Half(htlc_min=2_000))])
    l1 = node_factory.get_node(gossip_store_file=gsfile.name)

    with pytest.raises(RpcError, match=r"ending 1999msat across 0x1x0/1 would violate htlc_min \(~2000msat\)"):
        l1.rpc.getroutes(source=nodemap[0],
                         destination=nodemap[1],
                         amount_msat=1999,
                         layers=[],
                         maxfee_msat=20_000_000,
                         final_cltv=10)


@pytest.mark.slow_test
def test_real_data(node_factory, bitcoind):
    # Route from Rusty's node to the top nodes
    # From tests/data/gossip-store-2024-09-22-node-map.xz:
    # Me: 3301:024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605:BLUEIRON
    # So we make l2 node 3301.
    outfile = tempfile.NamedTemporaryFile(prefix='gossip-store-')
    nodeids = subprocess.check_output(['devtools/gossmap-compress',
                                       'decompress',
                                       '--node-map=3301=022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59',
                                       'tests/data/gossip-store-2024-09-22.compressed',
                                       outfile.name]).decode('utf-8').splitlines()

    # This is in msat, but is also the size of channel we create.
    AMOUNT = 100000000

    # l2 complains being given bad gossip from l1, throttle to reduce
    # the sheer amount of log noise.
    l1, l2 = node_factory.line_graph(2, fundamount=AMOUNT,
                                     opts=[{'gossip_store_file': outfile.name,
                                            'allow_warning': True,
                                            'dev-throttle-gossip': None},
                                           {'allow_warning': True}])

    # These were obviously having a bad day at the time of the snapshot:
    badnodes = {
        # 62:03dbe3fedd4f6e7f7020c69e6d01453d5a69f9faa1382901cf3028f1e997ef2814:BTC_👽👽👽👽👽👽
        62: " marked disabled by gossip message",
        # This one has 151 channels, with peers each only connected to it.  An island!
        # 76:0298906458987af756e2a43b208c03499c4d2bde630d4868dda0ea6a184f87c62a:0298906458987af756e2
        76: "There is no connection between source and destination at all",
        # 80:02d246c519845e7b23b02684d64ca23b750958e0307f9519849ee2535e3637999a:SLIMYRAGE-
        80: " marked disabled by gossip message",
        # 97:034a5fdb2df3ce1bfd2c2aca205ce9cfeef1a5f4af21b0b5e81c453080c30d7683:🚶LightningTransact
        97: r"We could not find a usable set of paths\.  The shortest path is 103x1x0->0x3301x1646->0x1281x2323->97x1281x33241, but 97x1281x33241/1 isn't big enough to carry 100000000msat\.",
    }

    # CI, it's slow.
    if SLOW_MACHINE:
        limit = 25
        expected = (6, 25, 1544756, 142986, 91)
    else:
        limit = 100
        expected = (9, 95, 6347877, 566288, 92)

    fees = {}
    for n in range(0, limit):
        print(f"XXX: {n}")
        # 0.5% is the norm
        MAX_FEE = AMOUNT // 200

        if n in badnodes:
            with pytest.raises(RpcError, match=badnodes[n]):
                l1.rpc.getroutes(source=l1.info['id'],
                                 destination=nodeids[n],
                                 amount_msat=AMOUNT,
                                 layers=['auto.sourcefree', 'auto.localchans'],
                                 maxfee_msat=MAX_FEE,
                                 final_cltv=18)
            fees[n] = []
            continue

        try:
            prev = l1.rpc.getroutes(source=l1.info['id'],
                                    destination=nodeids[n],
                                    amount_msat=AMOUNT,
                                    layers=['auto.sourcefree', 'auto.localchans'],
                                    maxfee_msat=MAX_FEE,
                                    final_cltv=18)
        except RpcError:
            fees[n] = []
            continue

        # Now stress it, by asking it to spend 1msat less!
        fees[n] = [sum([r['path'][0]['amount_msat'] for r in prev['routes']]) - AMOUNT]

        while True:
            # Keep making it harder...
            try:
                routes = l1.rpc.getroutes(source=l1.info['id'],
                                          destination=nodeids[n],
                                          amount_msat=AMOUNT,
                                          layers=['auto.sourcefree', 'auto.localchans'],
                                          maxfee_msat=fees[n][-1] - 1,
                                          final_cltv=18)
            except RpcError:
                break

            fee = sum([r['path'][0]['amount_msat'] for r in routes['routes']]) - AMOUNT
            # Should get less expensive
            assert fee < fees[n][-1]

            # Should get less likely (Note!  This is violated because once we care
            # about fees, the total is reduced, leading to better prob!).
#            assert routes['probability_ppm'] < prev['probability_ppm']

            fees[n].append(fee)
            prev = routes

    # Which succeeded in improving
    improved = [n for n in fees if len(fees[n]) > 1]
    total_first_fee = sum([fees[n][0] for n in improved])
    total_final_fee = sum([fees[n][-1] for n in improved])

    if total_first_fee != 0:
        percent_fee_reduction = 100 - int(total_final_fee * 100 / total_first_fee)
    else:
        percent_fee_reduction = 0

    best = 0
    for n in fees:
        if len(fees[n]) > len(fees[best]):
            best = n

    assert (len(fees[best]), len(improved), total_first_fee, total_final_fee, percent_fee_reduction) == expected


@pytest.mark.slow_test
def test_real_biases(node_factory, bitcoind):
    # Route from Rusty's node to the top 100.
    # From tests/data/gossip-store-2024-09-22-node-map.xz:
    # Me: 3301:024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605:BLUEIRON
    # So we make l2 node 3301.
    outfile = tempfile.NamedTemporaryFile(prefix='gossip-store-')
    nodeids = subprocess.check_output(['devtools/gossmap-compress',
                                       'decompress',
                                       '--node-map=3301=022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59',
                                       'tests/data/gossip-store-2024-09-22.compressed',
                                       outfile.name]).decode('utf-8').splitlines()

    # This is in msat, but is also the size of channel we create.
    AMOUNT = 100000000

    # l2 complains being given bad gossip from l1, throttle to reduce
    # the sheer amount of log noise.
    l1, l2 = node_factory.line_graph(2, fundamount=AMOUNT,
                                     opts=[{'gossip_store_file': outfile.name,
                                            'allow_warning': True,
                                            'dev-throttle-gossip': None},
                                           {'allow_warning': True}])

    # These were obviously having a bad day at the time of the snapshot:
    badnodes = {
        # 62:03dbe3fedd4f6e7f7020c69e6d01453d5a69f9faa1382901cf3028f1e997ef2814:BTC_👽👽👽👽👽👽
        62: " marked disabled by gossip message",
        # This one has 151 channels, with peers each only connected to it.  An island!
        # 76:0298906458987af756e2a43b208c03499c4d2bde630d4868dda0ea6a184f87c62a:0298906458987af756e2
        76: "There is no connection between source and destination at all",
        # 80:02d246c519845e7b23b02684d64ca23b750958e0307f9519849ee2535e3637999a:SLIMYRAGE-
        80: " marked disabled by gossip message",
        # 97:034a5fdb2df3ce1bfd2c2aca205ce9cfeef1a5f4af21b0b5e81c453080c30d7683:🚶LightningTransact
        97: r"We could not find a usable set of paths\.  The shortest path is 103x1x0->0x3301x1646->0x1281x2323->97x1281x33241, but 97x1281x33241/1 isn't big enough to carry 100000000msat\.",
    }

    # CI, it's slow.
    if SLOW_MACHINE:
        limit = 25
        expected = ({1: 5, 2: 7, 4: 7, 8: 11, 16: 14, 32: 19, 64: 25, 100: 25}, 0)
    else:
        limit = 100
        expected = ({1: 23, 2: 31, 4: 40, 8: 53, 16: 70, 32: 82, 64: 96, 100: 96}, 0)

    l1.rpc.askrene_create_layer('biases')
    num_changed = {}
    bias_ineffective = 0

    for bias in (1, 2, 4, 8, 16, 32, 64, 100):
        num_changed[bias] = 0
        for n in range(0, limit):
            # 0.5% is the norm
            MAX_FEE = AMOUNT // 200

            if n in badnodes:
                continue

            route = l1.rpc.getroutes(source=l1.info['id'],
                                     destination=nodeids[n],
                                     amount_msat=AMOUNT,
                                     layers=['auto.sourcefree', 'auto.localchans'],
                                     maxfee_msat=MAX_FEE,
                                     final_cltv=18)

            # Now add bias against final channel, see if it changes.
            chan = route['routes'][0]['path'][-1]['short_channel_id_dir']

            def amount_through_chan(chan, routes):
                total = 0
                for r in routes:
                    for p in r['path']:
                        if p['short_channel_id_dir'] == chan:
                            total += p['amount_msat']
                return total
            amount_before = amount_through_chan(chan, route['routes'])

            l1.rpc.askrene_bias_channel('biases', chan, -bias)
            route2 = l1.rpc.getroutes(source=l1.info['id'],
                                      destination=nodeids[n],
                                      amount_msat=AMOUNT,
                                      layers=['auto.sourcefree', 'auto.localchans', 'biases'],
                                      maxfee_msat=MAX_FEE,
                                      final_cltv=18)
            if route2 != route:
                # It should have avoided biassed channel
                amount_after = amount_through_chan(chan, route2['routes'])
                if amount_after < amount_before:
                    num_changed[bias] += 1
                else:
                    # We bias -4 against 83x88x31908/0 going to node 83, and this is violated.
                    # Both routes contain three paths, all via 83x88x31908/0.
                    # The first amounts  49490584, 1018832, 49490584,
                    # The second amounts 25254708, 25254708, 49490584,
                    # Due to fees and rounding, we actually spend 1msat more on the second case!
                    assert (n, bias, chan) == (83, 4, '83x88x31908/0')

            # Undo bias
            l1.rpc.askrene_bias_channel(layer='biases', short_channel_id_dir=chan, bias=0)

            # If it didn't change, try eliminating channel.
            if route2 == route and bias == 100:
                l1.rpc.askrene_update_channel(layer='biases',
                                              short_channel_id_dir=chan,
                                              enabled=False)
                try:
                    l1.rpc.getroutes(source=l1.info['id'],
                                     destination=nodeids[n],
                                     amount_msat=AMOUNT,
                                     layers=['auto.sourcefree', 'auto.localchans', 'biases'],
                                     maxfee_msat=MAX_FEE,
                                     final_cltv=18)
                    bias_ineffective += 1
                except RpcError:
                    pass
                l1.rpc.askrene_update_channel(layer='biases',
                                              short_channel_id_dir=chan,
                                              enabled=True)

    # With e^(-bias / (100/ln(30))):
    assert (num_changed, bias_ineffective) == expected


@pytest.mark.slow_test
def test_askrene_fake_channeld(node_factory, bitcoind):
    outfile = tempfile.NamedTemporaryFile(prefix='gossip-store-')
    nodeids = subprocess.check_output(['devtools/gossmap-compress',
                                       'decompress',
                                       '--node-map=3301=022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59',
                                       'tests/data/gossip-store-2024-09-22.compressed',
                                       outfile.name]).decode('utf-8').splitlines()
    AMOUNT = 100_000_000

    # l2 will warn l1 about its invalid gossip: ignore.
    # We throttle l1's gossip to avoid massive log spam.
    l1, l2 = node_factory.line_graph(2,
                                     # This is in sats, so 1000x amount we send.
                                     fundamount=AMOUNT,
                                     opts=[{'gossip_store_file': outfile.name,
                                            'subdaemon': 'channeld:../tests/plugins/channeld_fakenet',
                                            'allow_warning': True,
                                            'dev-throttle-gossip': None},
                                           {'allow_bad_gossip': True}])

    # l1 needs to know l2's shaseed for the channel so it can make revocations
    hsmfile = os.path.join(l2.daemon.lightning_dir, TEST_NETWORK, "hsm_secret")
    # Needs peer node id and channel dbid (1, it's the first channel), prints out:
    # "shaseed: xxxxxxx\n"
    shaseed = subprocess.check_output(["tools/hsmtool", "dumpcommitments", l1.info['id'], "1", "0", hsmfile]).decode('utf-8').strip().partition(": ")[2]
    l1.rpc.dev_peer_shachain(l2.info['id'], shaseed)

    TEMPORARY_CHANNEL_FAILURE = 0x1007
    MPP_TIMEOUT = 0x17

    l1.rpc.askrene_create_layer('test_askrene_fake_channeld')
    for n in range(0, 100):
        if n in (62, 76, 80, 97):
            continue

        print(f"PAYING Node #{n}")
        success = False
        while not success:
            routes = l1.rpc.getroutes(source=l1.info['id'],
                                      destination=nodeids[n],
                                      amount_msat=AMOUNT,
                                      layers=['auto.sourcefree', 'auto.localchans'],
                                      maxfee_msat=AMOUNT,
                                      final_cltv=18)

            preimage_hex = f'{n:02}' + '00' * 31
            hash_hex = sha256(bytes.fromhex(preimage_hex)).hexdigest()

            paths = {}
            # Sendpay wants a different format, so we convert.
            for i, r in enumerate(routes['routes']):
                paths[i] = [{'id': h['next_node_id'],
                             'channel': h['short_channel_id_dir'].split('/')[0],
                             'direction': int(h['short_channel_id_dir'].split('/')[1])}
                            for h in r['path']]

                # delay and amount_msat for sendpay are amounts at *end* of hop, not start!
                with_end = r['path'] + [{'amount_msat': r['amount_msat'], 'delay': r['final_cltv']}]
                for n, h in enumerate(paths[i]):
                    h['delay'] = with_end[n + 1]['delay']
                    h['amount_msat'] = with_end[n + 1]['amount_msat']

                l1.rpc.sendpay(paths[i], hash_hex,
                               amount_msat=AMOUNT,
                               payment_secret='00' * 32,
                               partid=i + 1, groupid=1)

            for i, p in paths.items():
                # Worst-case timeout is 1 second per hop, + 60 seconds if MPP timeout!
                try:
                    if l1.rpc.waitsendpay(hash_hex, timeout=TIMEOUT + len(p) + 60, partid=i + 1, groupid=1):
                        success = True
                except RpcError as err:
                    # Timeout means this one succeeded!
                    if err.error['data']['failcode'] == MPP_TIMEOUT:
                        for h in p:
                            l1.rpc.askrene_inform_channel('test_askrene_fake_channeld',
                                                          f"{h['channel']}/{h['direction']}",
                                                          h['amount_msat'],
                                                          'unconstrained')
                    elif err.error['data']['failcode'] == TEMPORARY_CHANNEL_FAILURE:
                        # We succeeded up to here
                        failpoint = err.error['data']['erring_index']
                        for h in p[:failpoint]:
                            l1.rpc.askrene_inform_channel('test_askrene_fake_channeld',
                                                          f"{h['channel']}/{h['direction']}",
                                                          h['amount_msat'],
                                                          'unconstrained')
                        h = p[failpoint]
                        l1.rpc.askrene_inform_channel('test_askrene_fake_channeld',
                                                      f"{h['channel']}/{h['direction']}",
                                                      h['amount_msat'],
                                                      'constrained')
                    else:
                        raise err