diff --git a/builtin/providers/aws/cloudfront_distribution_configuration_structure_test.go b/builtin/providers/aws/cloudfront_distribution_configuration_structure_test.go
index aa82b8329..7192c3193 100644
--- a/builtin/providers/aws/cloudfront_distribution_configuration_structure_test.go
+++ b/builtin/providers/aws/cloudfront_distribution_configuration_structure_test.go
@@ -56,7 +56,7 @@ func lambdaSetHash(v interface{}) int {
 		buf.WriteString(fmt.Sprintf("%s-", v.(string)))
 	}
 	if v, ok := m["lambda_arn"]; ok {
-		buf.WriteString(fmt.Sprintf("%d-", v.(string)))
+		buf.WriteString(fmt.Sprintf("%s-", v.(string)))
 	}
 	return hashcode.String(buf.String())
 }