Implement a redundant validation of JsonApiCondition scheme (RFC)

nucypher/policy/conditions/lingo.py

@@ -323,6 +323,15 @@ class ReturnValueTest:
         value = _resolve_context_variable(self.value, **context)
         return ReturnValueTest(self.comparator, value=value, index=self.index)
 
+    def as_dict(self):
+        result = {
+            "comparator": self.comparator,
+            "value": self.value,
+        }
+        if self.index is not None:
+            result["index"] = self.index
+        return result
+
 
 class ConditionLingo(_Serializable):
     VERSION = "1.0.0"

nucypher/policy/conditions/offchain.py

@@ -10,6 +10,7 @@ from nucypher.policy.conditions.base import AccessControlCondition
 from nucypher.policy.conditions.exceptions import (
     ConditionEvaluationFailed,
     InvalidCondition,
+    InvalidConditionLingo,
 )
 from nucypher.policy.conditions.lingo import ConditionType, ReturnValueTest
 from nucypher.policy.conditions.utils import CamelCaseSchema
@@ -83,6 +84,20 @@ class JsonApiCondition(AccessControlCondition):
                 f"{self.__class__.__name__} must be instantiated with the {self.CONDITION_TYPE} type."
             )
 
+        # validate inputs using marshmallow schema
+        data = {
+            "conditionType": condition_type,
+            "endpoint": endpoint,
+            "query": query,
+            "returnValueTest": return_value_test.as_dict(),
+        }
+        if parameters:
+            data["parameters"] = parameters
+        schema = self.Schema()
+        errors = schema.validate(data)
+        if errors:
+            raise InvalidConditionLingo(errors)
+
         self.endpoint = endpoint
         self.parameters = parameters
         self.query = query