diff --git a/examples/factories/project-factory/main.tf b/examples/factories/project-factory/main.tf
index 4efdaeac0..774fc1d64 100644
--- a/examples/factories/project-factory/main.tf
+++ b/examples/factories/project-factory/main.tf
@@ -24,10 +24,11 @@ locals {
   }
   _group_iam_bindings = distinct(flatten(values(var.group_iam)))
   # internal structures for project service accounts IAM bindings
+  _project_id = var.prefix == null || var.prefix == "" ? var.project_id : "${var.prefix}-${var.project_id}"
   _service_accounts_iam = {
     for r in local._service_accounts_iam_bindings : r => [
       for k, v in var.service_accounts :
-      "serviceAccount:${k}@${var.project_id}.iam.gserviceaccount.com"
+      "serviceAccount:${k}@${local._project_id}.iam.gserviceaccount.com"
       if try(index(v, r), null) != null
     ]
   }
diff --git a/tests/doc_examples/__init__.py b/tests/doc_examples/__init__.py
index e69de29bb..6d6d1266c 100644
--- a/tests/doc_examples/__init__.py
+++ b/tests/doc_examples/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2022 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.