diff --git a/certbot/plugins/dns_test_common.py b/certbot/plugins/dns_test_common.py
index f22d5a1a4..281b807cb 100644
--- a/certbot/plugins/dns_test_common.py
+++ b/certbot/plugins/dns_test_common.py
@@ -8,7 +8,6 @@ import six
 from acme import challenges
 
 from certbot import achallenges
-from certbot.compat import os
 from certbot.compat import security
 from certbot.tests import acme_util
 from certbot.tests import util as test_util
diff --git a/certbot/tests/compat/security_test.py b/certbot/tests/compat/security_test.py
new file mode 100644
index 000000000..d28dcc32d
--- /dev/null
+++ b/certbot/tests/compat/security_test.py
@@ -0,0 +1,22 @@
+"""Unit test for security module."""
+from certbot.compat import os
+from certbot.compat import security
+from certbot.tests.util import TempDirTestCase
+
+
+class SecurityTest(TempDirTestCase):
+    """Unit tests for security module."""
+    def test_check_modes(self):
+        probe = os.path.join(self.tempdir, 'probe')
+
+        open(probe, 'w').close()
+
+        security.chmod(probe, 0o755)
+
+        # TODO: add assertion when check_mode is implemented
+        #self.assertTrue(security.check_mode(probe, 0o755))
+
+        security.chmod(probe, 0o700)
+
+        # TODO: add assertion when check_mode is implemented
+        #self.assertFalse(security.check_mode(probe, 0o755))