diff --git a/tests/test_awslambda/test_lambda_cloudformation.py b/tests/test_awslambda/test_lambda_cloudformation.py
index ac960054a..a5d4d23fd 100644
--- a/tests/test_awslambda/test_lambda_cloudformation.py
+++ b/tests/test_awslambda/test_lambda_cloudformation.py
@@ -127,7 +127,7 @@ def get_template(bucket_name, version, runtime):
 
 def get_role_arn():
     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: