diff --git a/api/controller/sysroot_unittest.py b/api/controller/sysroot_unittest.py
index cd335ee..789f4f8 100644
--- a/api/controller/sysroot_unittest.py
+++ b/api/controller/sysroot_unittest.py
@@ -9,6 +9,7 @@
 
 import datetime
 import os
+import sys
 
 from chromite.api import api_config
 from chromite.api import controller
@@ -24,6 +25,9 @@
 from chromite.service import sysroot as sysroot_service
 
 
+assert sys.version_info >= (3, 6), 'This module requires Python 3.6+'
+
+
 class CreateTest(cros_test_lib.MockTestCase, api_config.ApiConfigMixin):
   """Create function tests."""