add fakewallet test throwing exceptions

cashu/core/settings.py

@@ -140,7 +140,9 @@ class FakeWalletSettings(MintSettings):
     fakewallet_delay_incoming_payment: Optional[float] = Field(default=3.0)
     fakewallet_stochastic_invoice: bool = Field(default=False)
     fakewallet_payment_state: Optional[str] = Field(default="SETTLED")
+    fakewallet_payment_state_exception: Optional[bool] = Field(default=False)
     fakewallet_pay_invoice_state: Optional[str] = Field(default="SETTLED")
+    fakewallet_pay_invoice_state_exception: Optional[bool] = Field(default=False)
 
 
 class MintInformation(CashuSettings):

cashu/lightning/fake.py

@@ -147,6 +147,9 @@ async def create_invoice(
         )
 
     async def pay_invoice(self, quote: MeltQuote, fee_limit: int) -> PaymentResponse:
+        if settings.fakewallet_pay_invoice_state_exception:
+            raise Exception("FakeWallet pay_invoice exception")
+
         invoice = decode(quote.request)
 
         if settings.fakewallet_delay_outgoing_payment:
@@ -189,6 +192,8 @@ async def get_invoice_status(self, checking_id: str) -> PaymentStatus:
             )
 
     async def get_payment_status(self, checking_id: str) -> PaymentStatus:
+        if settings.fakewallet_payment_state_exception:
+            raise Exception("FakeWallet get_payment_status exception")
         if settings.fakewallet_payment_state:
             return PaymentStatus(
                 result=PaymentResult[settings.fakewallet_payment_state]

cashu/mint/ledger.py

@@ -943,7 +943,7 @@ async def melt(
                     melt_quote, melt_quote.fee_reserve * 1000
                 )
                 logger.debug(
-                    f"Melt – Result: {payment.result}: preimage: {payment.preimage},"
+                    f"Melt – Result: {payment.result.name}: preimage: {payment.preimage},"
                     f" fee: {payment.fee.str() if payment.fee is not None else 'None'}"
                 )
                 if (
@@ -967,7 +967,7 @@ async def melt(
                     # explicitly check payment status for failed or unknown payment states
                     checking_id = payment.checking_id or melt_quote.checking_id
                     logger.debug(
-                        f"Payment state is {payment.result}. Checking status for {checking_id}"
+                        f"Payment state is {payment.result.name}.{' Error: ' + payment.error_message + '.' if payment.error_message else ''} Checking status for {checking_id}."
                     )
                     try:
                         status = await self.backends[method][unit].get_payment_status(
@@ -988,13 +988,17 @@ async def melt(
                             await self.db_write._unset_melt_quote_pending(
                                 quote=melt_quote, state=previous_state
                             )
+                            if status.error_message:
+                                logger.error(
+                                    f"Status check error: {status.error_message}"
+                                )
                             raise LightningError(
-                                f"Lightning payment failed: {payment.error_message}. Error: {status.error_message}"
+                                f"Lightning payment failed{': ' + payment.error_message if payment.error_message else ''}."
                             )
                         case _:
-                            # Status check returned different result than payment. Something must be wrong with our implementation or the backend. Keep transaction pending and return.
+                            # Something went wrong with our implementation or the backend. Status check returned different result than payment. Keep transaction pending and return.
                             logger.error(
-                                f"Payment state is {status.result} and payment was {payment.result}. Proofs for melt quote {melt_quote.quote} are stuck as PENDING. Disabling melt. Fix your Lightning backend and restart the mint."
+                                f"Payment state is {status.result.name} and payment was {payment.result}. Proofs for melt quote {melt_quote.quote} are stuck as PENDING. Disabling melt. Fix your Lightning backend and restart the mint."
                             )
                             self.disable_melt = True
                             return PostMeltQuoteResponse.from_melt_quote(melt_quote)
@@ -1013,7 +1017,9 @@ async def melt(
                     # NOTE: This is the only branch for a successful payment
 
                 case PaymentResult.PENDING | _:
-                    logger.debug(f"Lightning payment is pending: {payment.checking_id}")
+                    logger.debug(
+                        f"Lightning payment is {payment.result.name}: {payment.checking_id}"
+                    )
                     return PostMeltQuoteResponse.from_melt_quote(melt_quote)
 
         # melt was successful (either internal or via backend), invalidate proofs

tests/test_mint_melt.py

@@ -295,3 +295,39 @@ async def test_melt_lightning_pay_invoice_failed_pending(
     # expect that proofs are pending
     states = await ledger.db_read.get_proofs_states([p.Y for p in wallet.proofs])
     assert all([s.pending for s in states])
+
+
+@pytest.mark.asyncio
+@pytest.mark.skipif(is_regtest, reason="only fake wallet")
+async def test_melt_lightning_pay_invoice_exception_exception(
+    ledger: Ledger, wallet: Wallet
+):
+    """Simulates the case where pay_invoice and get_payment_status raise an exception (due to network issues for example)."""
+    invoice = await wallet.request_mint(64)
+    await ledger.get_mint_quote(invoice.id)  # fakewallet: set the quote to paid
+    await wallet.mint(64, id=invoice.id)
+    # invoice_64_sat = "lnbcrt640n1pn0r3tfpp5e30xac756gvd26cn3tgsh8ug6ct555zrvl7vsnma5cwp4g7auq5qdqqcqzzsxqyz5vqsp5xfhtzg0y3mekv6nsdnj43c346smh036t4f8gcfa2zwpxzwcryqvs9qxpqysgqw5juev8y3zxpdu0mvdrced5c6a852f9x7uh57g6fgjgcg5muqzd5474d7xgh770frazel67eejfwelnyr507q46hxqehala880rhlqspw07ta0"
+    invoice_62_sat = "lnbcrt620n1pn0r3vepp5zljn7g09fsyeahl4rnhuy0xax2puhua5r3gspt7ttlfrley6valqdqqcqzzsxqyz5vqsp577h763sel3q06tfnfe75kvwn5pxn344sd5vnays65f9wfgx4fpzq9qxpqysgqg3re9afz9rwwalytec04pdhf9mvh3e2k4r877tw7dr4g0fvzf9sny5nlfggdy6nduy2dytn06w50ls34qfldgsj37x0ymxam0a687mspp0ytr8"
+    quote_id = (
+        await ledger.melt_quote(
+            PostMeltQuoteRequest(unit="sat", request=invoice_62_sat)
+        )
+    ).quote
+    # quote = await ledger.get_melt_quote(quote_id)
+    settings.fakewallet_payment_state_exception = True
+    settings.fakewallet_pay_invoice_state_exception = True
+
+    # we expect a pending melt quote because something has gone wrong (for example has lost connection to backend)
+    resp = await ledger.melt(proofs=wallet.proofs, quote=quote_id)
+    assert resp.state == MeltQuoteState.pending.value
+
+    # the mint should be locked now and not allow any other melts until it is restarted
+    quote_id = (
+        await ledger.melt_quote(
+            PostMeltQuoteRequest(unit="sat", request=invoice_62_sat)
+        )
+    ).quote
+    await assert_err(
+        ledger.melt(proofs=wallet.proofs, quote=quote_id),
+        "Melt is disabled. Please contact the operator.",
+    )