Specify region name when creating Lambda roles

tests/test_awslambda/test_lambda.py

@@ -1549,7 +1549,7 @@ def create_invalid_lambda(role):
 
 def get_role_name():
     with mock_iam():
-        iam = boto3.client("iam")
+        iam = boto3.client("iam", region_name="us-west-2")
         try:
             return iam.get_role(RoleName="my-role")["Role"]["Arn"]
         except ClientError:

tests/test_cloudformation/test_cloudformation_stack_crud.py

@@ -598,7 +598,7 @@ def test_create_stack_kinesis():
 
 def get_role_name():
     with mock_iam():
-        iam = boto3.client("iam")
+        iam = boto3.client("iam", region_name="us-west-2")
         return iam.create_role(
             RoleName="TestRole", AssumeRolePolicyDocument="some_policy"
         )["Role"]["Arn"]