feat: Additional validation for Path model in cases involving mpt_issuance_id

Author: ckeshava

tests/unit/models/test_path.py

@@ -0,0 +1,61 @@
+from unittest import TestCase
+
+from xrpl.models.exceptions import XRPLModelException
+from xrpl.models.path import PathStep
+
+_ACCOUNT = "r9LqNeG6qHxjeUocjvVki2XR35weJ9mZgQ"
+_ISSUER = "rpGtkFRXhgVaBzC5XCR7gyE2AZN5SN3SEW"
+_MPT_ID = "00000001A407AF5856CECE4281FED12B7B179B49A4AEF506"
+
+
+class TestPathStepMPT(TestCase):
+    # --- valid cases ---
+
+    def test_valid_mpt_issuance_id_only(self):
+        step = PathStep(mpt_issuance_id=_MPT_ID)
+        self.assertTrue(step.is_valid())
+
+    def test_valid_account_only(self):
+        step = PathStep(account=_ACCOUNT)
+        self.assertTrue(step.is_valid())
+
+    # --- account + mpt_issuance_id ---
+
+    def test_account_with_mpt_issuance_id(self):
+        with self.assertRaises(XRPLModelException) as ctx:
+            PathStep(account=_ACCOUNT, mpt_issuance_id=_MPT_ID)
+        self.assertIn(
+            "Cannot set account if mpt_issuance_id is specified",
+            ctx.exception.args[0],
+        )
+
+    # --- currency + mpt_issuance_id ---
+
+    def test_currency_with_mpt_issuance_id(self):
+        with self.assertRaises(XRPLModelException) as ctx:
+            PathStep(currency="USD", mpt_issuance_id=_MPT_ID)
+        self.assertIn(
+            "Cannot set both currency and mpt_issuance_id",
+            ctx.exception.args[0],
+        )
+
+    # --- mpt_issuance_id + currency (from mpt validator) ---
+
+    def test_mpt_issuance_id_with_currency(self):
+        """Same combo as above, but verifies the mpt_issuance_id validator's message."""
+        with self.assertRaises(XRPLModelException) as ctx:
+            PathStep(mpt_issuance_id=_MPT_ID, currency="USD")
+        self.assertIn(
+            "Cannot set both mpt_issuance_id and currency",
+            ctx.exception.args[0],
+        )
+
+    # --- mpt_issuance_id + account (from mpt validator) ---
+
+    def test_mpt_issuance_id_with_account(self):
+        with self.assertRaises(XRPLModelException) as ctx:
+            PathStep(mpt_issuance_id=_MPT_ID, account=_ACCOUNT)
+        self.assertIn(
+            "Cannot set both mpt_issuance_id and account",
+            ctx.exception.args[0],
+        )

xrpl/models/path.py

@@ -44,6 +44,8 @@ def _get_account_error(self: Self) -> Optional[str]:
             return None
         if self.currency is not None or self.issuer is not None:
             return "Cannot set account if currency or issuer are set"
+        if self.mpt_issuance_id is not None:
+            return "Cannot set account if mpt_issuance_id is specified"
         return None
 
     def _get_currency_error(self: Self) -> Optional[str]:
@@ -71,6 +73,8 @@ def _get_mpt_issuance_id_error(self: Self) -> Optional[str]:
             return None
         if self.currency is not None:
             return "Cannot set both mpt_issuance_id and currency"
+        if self.account is not None:
+            return "Cannot set both mpt_issuance_id and account"
         return None