Simplify test setup for Template List model

tests/app/models/test_template_list.py

@@ -1,5 +1,7 @@
 import uuid
 
+import pytest
+
 from app.models.service import Service
 from app.models.template_list import TemplateList
 from app.models.user import User
@@ -10,8 +12,12 @@ VIS_PARENT_FOLDER_ID = 'bbbb222b-2b22-2b22-222b-b222b22b2222'
 INV_CHILD_2_FOLDER_ID = 'fafe723f-1d39-4a10-865f-e551e03d8886'
 
 
-def _get_all_folders(active_user_with_permissions):
-    return [
+@pytest.fixture
+def mock_get_hierarchy_of_folders(
+    mock_get_template_folders,
+    active_user_with_permissions
+):
+    mock_get_template_folders.return_value = [
         {
             'name': "Invisible folder",
             'id': str(uuid.uuid4()),
@@ -70,14 +76,11 @@ def _get_all_folders(active_user_with_permissions):
 
 
 def test_template_list_yields_folders_visible_to_user(
-    notify_admin,
-    mock_get_template_folders,
+    mock_get_hierarchy_of_folders,
     mock_get_service_templates,
     service_one,
     active_user_with_permissions,
-    mocker
 ):
-    mock_get_template_folders.return_value = _get_all_folders(active_user_with_permissions)
     service = Service(service_one)
     user = User(active_user_with_permissions)
 
@@ -97,13 +100,10 @@ def test_template_list_yields_folders_visible_to_user(
 
 
 def test_template_list_yields_all_folders_without_user(
-    mock_get_template_folders,
+    mock_get_hierarchy_of_folders,
     mock_get_service_templates,
     service_one,
-    active_user_with_permissions,
-    mocker
 ):
-    mock_get_template_folders.return_value = _get_all_folders(active_user_with_permissions)
     service = Service(service_one)
 
     result_folder_names = tuple(