diff --git a/letsencrypt/tests/cli_test.py b/letsencrypt/tests/cli_test.py
index 584e67feb..c38ece0e1 100644
--- a/letsencrypt/tests/cli_test.py
+++ b/letsencrypt/tests/cli_test.py
@@ -176,7 +176,8 @@ class DuplicativeCertsTest(renewer_test.BaseRenewableCertTest):
     def tearDown(self):
         shutil.rmtree(self.tempdir)
 
-    def test_find_duplicative_names(self):
+    @mock.patch("letsencrypt.le_util.make_or_verify_dir")
+    def test_find_duplicative_names(self, unused):
         from letsencrypt.cli import _find_duplicative_certs
         test_cert = test_util.load_vector("cert-san.pem")
         with open(self.test_rc.cert, "w") as f: