Merge pull request #6425 from LewisGaul/replace-route-invalidparametervalue

EC2: Return appropriate error when calling EC2.Client.replace_route() with missing route

moto/ec2/exceptions.py

@@ -444,6 +444,14 @@ class InvalidParameterValueErrorTagSpotFleetRequest(EC2ClientError):
         )
 
 
+class InvalidParameterValueErrorReplaceRoute(EC2ClientError):
+    def __init__(self, cidr: str):
+        super().__init__(
+            "InvalidParameterValue",
+            f"There is no route defined for '{cidr}' in the route table. Use CreateRoute instead.",
+        )
+
+
 class EmptyTagSpecError(EC2ClientError):
     def __init__(self) -> None:
         super().__init__(

moto/ec2/models/route_tables.py

@@ -18,6 +18,7 @@ from ..exceptions import (
     InvalidRouteTableIdError,
     InvalidAssociationIdError,
     InvalidDestinationCIDRBlockParameterError,
+    InvalidParameterValueErrorReplaceRoute,
     RouteAlreadyExistsError,
     RouteNotSupportedError,
 )
@@ -447,11 +448,22 @@ class RouteBackend:
         interface_id: Optional[str] = None,
         vpc_peering_connection_id: Optional[str] = None,
     ) -> Route:
+        cidr = destination_cidr_block
+        if destination_ipv6_cidr_block:
+            cidr = destination_ipv6_cidr_block
+        if destination_prefix_list_id:
+            cidr = destination_prefix_list_id
         route_table = self.get_route_table(route_table_id)
         route_id = generate_route_id(
             route_table.id, destination_cidr_block, destination_ipv6_cidr_block
         )
-        route = route_table.routes[route_id]
+        try:
+            route = route_table.routes[route_id]
+        except KeyError:
+            # This should be 'raise InvalidRouteError(route_table_id, cidr)' in
+            # line with the delete_route() equivalent, but for some reason AWS
+            # returns InvalidParameterValue instead in this case.
+            raise InvalidParameterValueErrorReplaceRoute(cidr) from None
 
         route.gateway = None
         route.nat_gateway = None

tests/test_ec2/test_route_tables.py

@@ -643,6 +643,18 @@ def test_routes_replace():
     ex.value.response["ResponseMetadata"].should.have.key("RequestId")
     ex.value.response["Error"]["Code"].should.equal("InvalidRouteTableID.NotFound")
 
+    with pytest.raises(ClientError) as ex:
+        client.replace_route(
+            RouteTableId=main_route_table.id,
+            DestinationCidrBlock="1.1.1.1/32",
+            NetworkInterfaceId=eni.id,
+        )
+    ex.value.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(400)
+    ex.value.response["ResponseMetadata"].should.have.key("RequestId")
+    # This should be 'InvalidRoute.NotFound' in line with the delete_route()
+    # equivalent, but for some reason AWS returns InvalidParameterValue instead.
+    ex.value.response["Error"]["Code"].should.equal("InvalidParameterValue")
+
 
 @mock_ec2
 def test_routes_already_exist():