cover test

certbot/reverter.py

@@ -7,6 +7,7 @@ import shutil
 import time
 import traceback
 
+
 import zope.component
 
 from certbot import constants

certbot/tests/reverter_test.py

@@ -34,6 +34,20 @@ class ReverterCheckpointLocalTest(unittest.TestCase):
 
         logging.disable(logging.NOTSET)
 
+    @mock.patch("certbot.reverter.Reverter._read_and_append")
+    def test_no_change(self, mock_read):
+        mock_read.side_effect = OSError("cannot even")
+        try:
+            self.reverter.add_to_checkpoint(self.sets[0], "save1")
+        except:
+            pass
+        self.reverter.finalize_checkpoint("blah")
+        path = os.listdir(self.reverter.config.backup_dir)[0]
+        no_change = os.path.join(self.reverter.config.backup_dir, path, "CHANGES_SINCE")
+        with open(no_change, "r") as f:
+            x = f.read()
+        self.assertTrue("No changes" in x)
+
     def test_basic_add_to_temp_checkpoint(self):
         # These shouldn't conflict even though they are both named config.txt
         self.reverter.add_to_temp_checkpoint(self.sets[0], "save1")