diff --git a/frappe/core/doctype/user/user.py b/frappe/core/doctype/user/user.py
index c19d0ae6f4..72ea4e58c7 100644
--- a/frappe/core/doctype/user/user.py
+++ b/frappe/core/doctype/user/user.py
@@ -638,6 +638,7 @@ class User(Document):
 	def add_roles(self, *roles):
 		"""Add roles to user and save"""
 		self.append_roles(*roles)
+		# test_user_permission.create_user depends on this
 		self.save()
 
 	def remove_roles(self, *roles):
diff --git a/frappe/core/doctype/user_permission/test_user_permission.py b/frappe/core/doctype/user_permission/test_user_permission.py
index 1c5862dce5..9cfdb7925e 100644
--- a/frappe/core/doctype/user_permission/test_user_permission.py
+++ b/frappe/core/doctype/user_permission/test_user_permission.py
@@ -306,6 +306,7 @@ def create_user(email, *roles):
 	if not roles:
 		roles = ("System Manager",)
 
+	# this triggers doc.save, so explicit save is not needed
 	user.add_roles(*roles)
 	return user