Create lightning client base class (#1542)

* Add unit test for add invoice in test lnd lightning client

* Add new create invoice method of lightning client and add unit test

docker/test/Dockerfile

@@ -7,7 +7,6 @@ RUN pip3 install -r requirements-itest.txt
 WORKDIR /app
 
 COPY proto ./proto
-COPY itests/test.sh squeaknode/lightning/lnd_lightning_client.py ./
 COPY itests/tests ./tests
 
 RUN python3 -m grpc_tools.protoc --proto_path=. --python_out=. --grpc_python_out=. \

itests/tests/conftest.py

@@ -35,7 +35,6 @@ from tests.util import create_signing_profile
 from tests.util import delete_profile
 from tests.util import generate_signing_key
 from tests.util import get_address
-from tests.util import load_lightning_client
 from tests.util import open_peer_connection
 
 
@@ -57,11 +56,6 @@ def other_admin_stub():
         yield squeak_admin_pb2_grpc.SqueakAdminStub(admin_channel)
 
 
-@pytest.fixture
-def lightning_client():
-    return load_lightning_client()
-
-
 @pytest.fixture
 def signing_key():
     # Create a signing key

itests/tests/test_squeak_node.py

@@ -30,7 +30,7 @@ from squeak.core import CSqueak
 
 from proto import lnd_pb2 as ln
 from proto import squeak_admin_pb2
-from tests.util import connect_peer
+from tests.util import channel
 from tests.util import create_contact_profile
 from tests.util import create_saved_peer
 from tests.util import create_signing_profile
@@ -50,8 +50,9 @@ from tests.util import get_squeak_display
 from tests.util import get_squeak_profile
 from tests.util import import_signing_profile
 from tests.util import make_squeak
-from tests.util import open_channel
 from tests.util import open_peer_connection
+from tests.util import peer_connection
+from tests.util import send_coins
 from tests.util import subscribe_connected_peers
 from tests.util import subscribe_squeak_ancestor_entries
 from tests.util import subscribe_squeak_entry
@@ -581,10 +582,10 @@ def test_delete_peer(admin_stub, peer_id):
     assert not get_peer_response.HasField("squeak_peer")
 
 
-def test_send_coins(admin_stub, lightning_client):
+def test_send_coins(admin_stub, other_admin_stub):
     new_address_response = admin_stub.LndNewAddress(ln.NewAddressRequest())
-    send_coins_response = lightning_client.send_coins(
-        new_address_response.address, 55555555
+    send_coins_response = send_coins(
+        other_admin_stub, new_address_response.address, 55555555
     )
     time.sleep(10)
     get_transactions_response = admin_stub.LndGetTransactions(
@@ -603,7 +604,6 @@ def test_buy_squeak(
     admin_stub,
     other_admin_stub,
     connected_tcp_peer_id,
-    lightning_client,
     signing_profile_id,
     saved_squeak_hash,
 ):
@@ -637,9 +637,9 @@ def test_buy_squeak(
     offer = get_buy_offers_response.offers[0]
 
     print("Tring to connect LND peer with offer: {}".format(offer))
-    with connect_peer(
-        lightning_client, offer.node_host, offer.node_pubkey
-    ), open_channel(lightning_client, offer.node_pubkey, 1000000):
+    with peer_connection(
+        other_admin_stub, offer.node_host, offer.node_pubkey
+    ), channel(other_admin_stub, offer.node_pubkey, 1000000):
 
         print("Channel context manager opened.")
 
@@ -759,7 +759,6 @@ def test_download_free_squeak(
     admin_stub,
     other_admin_stub,
     connected_tcp_peer_id,
-    lightning_client,
     signing_profile_id_with_free_price,
     saved_squeak_hash,
 ):
@@ -783,7 +782,6 @@ def test_download_single_squeak(
     admin_stub,
     other_admin_stub,
     connected_tcp_peer_id,
-    lightning_client,
     signing_profile_id,
     saved_squeak_hash,
 ):
@@ -999,7 +997,6 @@ def test_get_squeak_by_lookup(
     admin_stub,
     other_admin_stub,
     connected_tcp_peer_id,
-    lightning_client,
     signing_profile_id,
     saved_squeak_hash,
 ):

itests/tests/util.py

@@ -27,13 +27,13 @@ import threading
 import time
 from contextlib import contextmanager
 
-from lnd_lightning_client import LNDLightningClient
 from squeak.core.elliptic import scalar_difference
 from squeak.core.elliptic import scalar_from_bytes
 from squeak.core.elliptic import scalar_to_bytes
 from squeak.core.signing import CSigningKey
 from squeak.core.signing import CSqueakAddress
 
+from proto import lnd_pb2
 from proto import squeak_admin_pb2
 
 
@@ -47,30 +47,12 @@ def get_address(signing_key):
     return str(address)
 
 
-def get_latest_block_info(lightning_client):
-    get_info_response = lightning_client.get_info()
-    block_hash = bytes.fromhex(get_info_response.block_hash)
-    block_height = get_info_response.block_height
-    return block_hash, block_height
-
-
 def get_hash(squeak):
     """ Needs to be reversed because hash is stored as little-endian """
     hash_bytes = squeak.GetHash()[::-1]
     return hash_bytes.hex()
 
 
-def load_lightning_client() -> LNDLightningClient:
-    tls_cert_path = "~/.lnd/tls.cert"
-    macaroon_path = "~/.lnd/data/chain/bitcoin/simnet/admin.macaroon"
-    return LNDLightningClient(
-        "lnd",
-        10009,
-        tls_cert_path,
-        macaroon_path,
-    )
-
-
 def string_to_hex(s):
     return bytes.fromhex(s)
 
@@ -88,33 +70,57 @@ def bytes_to_base64_string(data: bytes) -> str:
 
 
 @contextmanager
-def connect_peer(lightning_client, lightning_host, remote_pubkey):
+def peer_connection(node_stub, lightning_host, remote_pubkey):
     # Connect the peer
-    lightning_client.connect_peer(remote_pubkey, lightning_host)
+    connect_peer(node_stub, remote_pubkey, lightning_host)
     try:
+        print("Yielding lnd peer is connected.")
         yield
     finally:
         # Disconnect the peer
-        lightning_client.disconnect_peer(
-            remote_pubkey,
-        )
+        disconnect_peer(node_stub, remote_pubkey)
         time.sleep(2)
 
 
 @contextmanager
-def open_channel(lightning_client, remote_pubkey, amount):
+def channel(node_stub, remote_pubkey, amount):
     # Open channel to the server lightning node
-    pubkey_bytes = string_to_hex(remote_pubkey)
-    open_channel_response = lightning_client.open_channel(pubkey_bytes, amount)
+    # pubkey_bytes = string_to_hex(remote_pubkey)
+    # open_channel_response = lightning_client.open_channel(pubkey_bytes, amount)
+    print("Trying to open channel...")
+    channel_point = open_channel(node_stub, remote_pubkey, amount)
     print("Opening channel...")
-    for update in open_channel_response:
-        if update.HasField("chan_open"):
-            channel_point = update.chan_open.channel_point
-            print("Channel now open: " + str(channel_point))
+
+    # Wait for channel to be open.
+    MAX_RETRIES = 30
+    i = 0
+    while True:
+        print("Try number: {}".format(i))
+        # peers_list = lightning_client.list_peers()
+        peers_list = list_peers(node_stub)
+        # channels_list = lightning_client.list_channels()
+        channels_list = list_channels(node_stub)
+        # pending_channels_list = lightning_client.pending_channels()
+        pending_channels_list = pending_channels(node_stub)
+        print("list peers: {}".format(peers_list))
+        print("list channels: {}".format(channels_list))
+        print("pending channels: {}".format(pending_channels_list))
+        if len(channels_list.channels) > 0:
+            print("Channel now open.")
             break
-    print("list peers: {}".format(lightning_client.list_peers()))
-    print("list channels: {}".format(lightning_client.list_channels()))
-    print("pending channels: {}".format(lightning_client.pending_channels()))
+        time.sleep(1)
+        i += 1
+        if i > MAX_RETRIES:
+            raise Exception("Open channel timed out.")
+
+    # for update in open_channel_response:
+    #     if update.HasField("chan_open"):
+    #         channel_point = update.chan_open.channel_point
+    #         print("Channel now open: " + str(channel_point))
+    #         break
+    # print("list peers: {}".format(lightning_client.list_peers()))
+    # print("list channels: {}".format(lightning_client.list_channels()))
+    # print("pending channels: {}".format(lightning_client.pending_channels()))
     time.sleep(10)
     try:
         yield
@@ -122,10 +128,8 @@ def open_channel(lightning_client, remote_pubkey, amount):
         # Code to release resource, e.g.:
         # Close the channel
         time.sleep(2)
-        for update in lightning_client.close_channel(channel_point):
-            if update.HasField("chan_close"):
-                print("Channel closed.")
-                break
+        # for update in lightning_client.close_channel(channel_point):
+        close_channel(node_stub, channel_point)
 
 
 @contextmanager
@@ -355,6 +359,71 @@ def delete_profile(node_stub, profile_id):
     )
 
 
+def open_channel(node_stub, remote_pubkey, amount):
+    return node_stub.LndOpenChannelSync(
+        lnd_pb2.OpenChannelRequest(
+            node_pubkey_string=remote_pubkey,
+            local_funding_amount=amount,
+        )
+    )
+
+
+def close_channel(node_stub, channel_point):
+    return node_stub.LndCloseChannel(
+        lnd_pb2.CloseChannelRequest(
+            channel_point=channel_point,
+        )
+    )
+
+
+def list_peers(node_stub):
+    return node_stub.LndListPeers(
+        lnd_pb2.ListPeersRequest()
+    )
+
+
+def list_channels(node_stub):
+    return node_stub.LndListChannels(
+        lnd_pb2.ListChannelsRequest()
+    )
+
+
+def pending_channels(node_stub):
+    return node_stub.LndPendingChannels(
+        lnd_pb2.PendingChannelsRequest()
+    )
+
+
+def connect_peer(node_stub, pubkey, host):
+    lightning_address = lnd_pb2.LightningAddress(
+        pubkey=pubkey,
+        host=host,
+    )
+    connect_peer_request = lnd_pb2.ConnectPeerRequest(
+        addr=lightning_address,
+    )
+    return node_stub.LndConnectPeer(connect_peer_request)
+
+
+def disconnect_peer(node_stub, pubkey):
+    disconnect_peer_request = lnd_pb2.DisconnectPeerRequest(
+        pub_key=pubkey,
+    )
+    return node_stub.LndDisconnectPeer(
+        disconnect_peer_request,
+    )
+
+
+def send_coins(node_stub, addr, amount):
+    send_coins_request = lnd_pb2.SendCoinsRequest(
+        addr=addr,
+        amount=amount,
+    )
+    return node_stub.LndSendCoins(
+        send_coins_request,
+    )
+
+
 @contextmanager
 def subscribe_squeak_entry(node_stub, squeak_hash):
     q = queue.Queue()

squeaknode/core/squeak_core.py

@@ -170,28 +170,19 @@ class SqueakCore:
         # Calculate the preimage
         preimage = add_tweak(secret_key, nonce)
         # Create the lightning invoice
-        add_invoice_response = self.lightning_client.add_invoice(
+        invoice = self.lightning_client.create_invoice(
             preimage, price_msat
         )
-        payment_hash = add_invoice_response.r_hash
-        invoice_payment_request = add_invoice_response.payment_request
-        # invoice_expiry = add_invoice_response.expiry
-        lookup_invoice_response = self.lightning_client.lookup_invoice(
-            payment_hash.hex()
-        )
-        invoice_time = lookup_invoice_response.creation_date
-        invoice_expiry = lookup_invoice_response.expiry
-        # Save the incoming potential payment in the databse.
         return SentOffer(
             sent_offer_id=None,
             squeak_hash=squeak_hash,
-            payment_hash=payment_hash,
-            secret_key=preimage,
+            payment_hash=invoice.r_hash,
+            secret_key=preimage,  # TODO: remove this field.
             nonce=nonce,
             price_msat=price_msat,
-            payment_request=invoice_payment_request,
-            invoice_time=invoice_time,
-            invoice_expiry=invoice_expiry,
+            payment_request=invoice.payment_request,
+            invoice_time=invoice.creation_date,
+            invoice_expiry=invoice.expiry,
             peer_address=peer_address,
         )
 

squeaknode/lightning/exception.py

@@ -0,0 +1,37 @@
+# MIT License
+#
+# Copyright (c) 2020 Jonathan Zernik
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+
+class LightningError(Exception):
+    """Base class for other lightning exceptions."""
+
+
+class LightningCommandError(LightningError):
+    """Error that is raised when the lightning RPC fails."""
+
+    def __init__(self, err):
+        self.err = err
+
+    def __repr__(self):
+        return 'LightningCommandError(%r)' % (
+            self.err,
+        )

squeaknode/lightning/invoice.py

@@ -0,0 +1,33 @@
+# MIT License
+#
+# Copyright (c) 2020 Jonathan Zernik
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+from typing import NamedTuple
+
+
+class Invoice(NamedTuple):
+    """Represents a lightning invoice."""
+    r_hash: bytes
+    payment_request: str
+    value_msat: int
+    settled: bool
+    settle_index: int
+    creation_date: int
+    expiry: int

squeaknode/lightning/lightning_client.py

@@ -0,0 +1,46 @@
+# MIT License
+#
+# Copyright (c) 2020 Jonathan Zernik
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+import logging
+from abc import ABC
+from abc import abstractmethod
+
+from squeaknode.lightning.invoice import Invoice
+
+logger = logging.getLogger(__name__)
+
+
+class LightningClient(ABC):
+
+    @abstractmethod
+    def create_invoice(self, preimage, amount_msat) -> Invoice:
+        """Add a new invoice.
+
+        Args:
+            preimage: The lightning invoice preimage.
+            amount_msat: The amount of the invoice in msats.
+
+        Returns:
+            Invoice: an object representing a lightning invoice.
+
+        Raises:
+            LightningRequestError: If the request fails.
+        """

squeaknode/lightning/lnd_lightning_client.py

@@ -27,6 +27,7 @@ import grpc
 
 from proto import lnd_pb2
 from proto import lnd_pb2_grpc
+from squeaknode.lightning.invoice import Invoice
 
 logger = logging.getLogger(__name__)
 
@@ -48,16 +49,26 @@ class LNDLightningClient:
         tls_cert_path: str,
         macaroon_path: str,
     ) -> None:
-        url = "{}:{}".format(host, port)
+        self.host = host
+        self.port = port
+        self.tls_cert_path = tls_cert_path
+        self.macaroon_path = macaroon_path
+        self.stub = None
+
+    def init(self):
+        self.stub = self._get_stub()
+
+    def _get_stub(self):
+        url = "{}:{}".format(self.host, self.port)
 
         # Lnd cert is at ~/.lnd/tls.cert on Linux and
         # ~/Library/Application Support/Lnd/tls.cert on Mac
-        cert = open(os.path.expanduser(tls_cert_path), "rb").read()
+        cert = open(os.path.expanduser(self.tls_cert_path), "rb").read()
         cert_creds = grpc.ssl_channel_credentials(cert)
 
         # Lnd admin macaroon is at ~/.lnd/data/chain/bitcoin/simnet/admin.macaroon on Linux and
         # ~/Library/Application Support/Lnd/data/chain/bitcoin/simnet/admin.macaroon on Mac
-        with open(os.path.expanduser(macaroon_path), "rb") as f:
+        with open(os.path.expanduser(self.macaroon_path), "rb") as f:
             macaroon_bytes = f.read()
             macaroon = codecs.encode(macaroon_bytes, "hex")
             self.macaroon = codecs.encode(macaroon_bytes, "hex")
@@ -76,7 +87,7 @@ class LNDLightningClient:
 
         # finally pass in the combined credentials when creating a channel
         channel = grpc.secure_channel(url, combined_creds)
-        self.stub = lnd_pb2_grpc.LightningStub(channel)
+        return lnd_pb2_grpc.LightningStub(channel)
 
     def get_wallet_balance(self):
         # Retrieve and display the wallet balance
@@ -269,3 +280,19 @@ class LNDLightningClient:
             r_hash_str=r_hash_str,
         )
         return self.stub.LookupInvoice(payment_hash)
+
+    def create_invoice(self, preimage, amount_msat) -> Invoice:
+        add_invoice_response = self.add_invoice(preimage, amount_msat)
+        payment_hash = add_invoice_response.r_hash
+        lookup_invoice_response = self.lookup_invoice(
+            payment_hash.hex()
+        )
+        return Invoice(
+            r_hash=lookup_invoice_response.r_hash,
+            payment_request=lookup_invoice_response.payment_request,
+            value_msat=amount_msat,
+            settled=lookup_invoice_response.settled,
+            settle_index=lookup_invoice_response.settle_index,
+            creation_date=lookup_invoice_response.creation_date,
+            expiry=lookup_invoice_response.expiry,
+        )

squeaknode/node/squeak_node.py

@@ -128,6 +128,7 @@ class SqueakNode:
             self.config.lnd.tls_cert_path,
             self.config.lnd.macaroon_path,
         )
+        self.lightning_client.init()
 
     def initialize_bitcoin_client(self):
         # load the bitcoin client

tests/lightning/test_lnd_lightning_client.py

@@ -0,0 +1,119 @@
+# MIT License
+#
+# Copyright (c) 2020 Jonathan Zernik
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+import mock
+import pytest
+
+from proto import lnd_pb2
+from squeaknode.lightning.lnd_lightning_client import LNDLightningClient
+from tests.utils import gen_random_hash
+
+
+@pytest.fixture
+def lnd_host():
+    yield "fake_lnd_host"
+
+
+@pytest.fixture
+def lnd_port():
+    yield 9876
+
+
+@pytest.fixture
+def tls_cert_path():
+    yield "fake_tls_cert_path"
+
+
+@pytest.fixture
+def macaroon_path():
+    yield "fake_macaroon_path"
+
+
+@pytest.fixture
+def preimage():
+    yield gen_random_hash()
+
+
+@pytest.fixture
+def price_msat():
+    yield 33333
+
+
+@pytest.fixture
+def rpc_invoice(preimage):
+    yield lnd_pb2.Invoice(
+        memo='hello',
+        r_preimage=preimage,
+    )
+
+
+# @pytest.fixture
+# def lnd_lightning_client_and_get_stub(lnd_host, lnd_port, tls_cert_path, macaroon_path):
+#     client = LNDLightningClient(
+#         host=lnd_host,
+#         port=lnd_port,
+#         tls_cert_path=tls_cert_path,
+#         macaroon_path=macaroon_path,
+#     )
+#     with mock.patch.object(client, '_get_stub', autospec=True) as mock_get_stub:
+#         yield client, mock_get_stub
+
+
+# @pytest.fixture
+# def lnd_lightning_client(lnd_lightning_client_and_get_stub):
+#     client, _ = lnd_lightning_client_and_get_stub
+#     yield client
+
+
+# @pytest.fixture
+# def mock_get_stub(lnd_lightning_client_and_get_stub):
+#     _, get_stub = lnd_lightning_client_and_get_stub
+#     yield get_stub
+
+
+@pytest.fixture
+def make_lightning_client(lnd_host, lnd_port, tls_cert_path, macaroon_path):
+    client = LNDLightningClient(
+        host=lnd_host,
+        port=lnd_port,
+        tls_cert_path=tls_cert_path,
+        macaroon_path=macaroon_path,
+    )
+    with mock.patch.object(client, '_get_stub', autospec=True) as mock_get_stub:
+        def fn(stub):
+            mock_get_stub.return_value = stub
+            client.init()
+            return client
+        yield fn
+
+
+def test_add_invoice(make_lightning_client, preimage, price_msat, rpc_invoice):
+    mock_stub = mock.MagicMock()
+    mock_stub.AddInvoice.return_value = rpc_invoice
+    client = make_lightning_client(mock_stub)
+    add_invoice_response = client.add_invoice(
+        preimage, price_msat)
+    (call_invoice,) = mock_stub.AddInvoice.call_args.args
+    print(call_invoice)
+
+    assert call_invoice.r_preimage == preimage
+    assert call_invoice.value_msat == price_msat
+    assert add_invoice_response == rpc_invoice