itest: add test paying again fails

itest/tests/test_pay_again_fails.py

@@ -0,0 +1,62 @@
+from binascii import hexlify
+from bitcoin.wallet import CBitcoinSecret
+from pyln.testing.fixtures import (
+    bitcoind,
+    directory,
+    db_provider,
+    executor,
+    jsonschemas,
+    node_cls,
+    node_factory,
+    setup_logging,
+    teardown_checks,
+    test_base_dir,
+    test_name,
+)
+from pyln.testing.utils import wait_for
+from fixtures import whatthefee, swapd_factory, postgres_factory
+import grpc
+import hashlib
+import os
+
+
+def test_pay_again_fails(node_factory, swapd_factory):
+    user = node_factory.get_node()
+    swapper = swapd_factory.get_swapd()
+    swapper.lightning_node.openchannel(user, 1000000)
+    wait_for(
+        lambda: all(
+            channel["state"] == "CHANNELD_NORMAL"
+            for channel in swapper.lightning_node.rpc.listpeerchannels()["channels"]
+        )
+    )
+    user_node_id = user.info["id"]
+    secret_key = CBitcoinSecret.from_secret_bytes(os.urandom(32))
+    public_key = secret_key.pub
+    preimage = os.urandom(32)
+    h = hashlib.sha256(preimage).digest()
+    add_fund_resp = swapper.rpc.add_fund_init(user, public_key, h)
+    txid = user.bitcoin.rpc.sendtoaddress(add_fund_resp.address, 100_000 / 10**8)
+    user.bitcoin.generate_block(1)
+
+    wait_for(
+        lambda: len(swapper.internal_rpc.get_swap(add_fund_resp.address).outputs) > 0
+    )
+
+    payment_request = user.rpc.invoice(
+        100_000_000,
+        "swap-success",
+        "swap-success",
+        preimage=hexlify(preimage).decode("ASCII"),
+    )["bolt11"]
+    swapper.rpc.get_swap_payment(payment_request)
+    wait_for(
+        lambda: user.rpc.listinvoices(payment_hash=hexlify(h).decode("ASCII"))[
+            "invoices"
+        ][0]["status"]
+        == "paid"
+    )
+    try:
+        swapper.rpc.get_swap_payment(payment_request)
+    except grpc._channel._InactiveRpcError as e:
+        assert e.details() == "swap already paid"