Refactor the __fetch_manifest() code so that the a successful response is immediately handled and we don't end up with an undefined 'response' on an exception. Also update the tests to return two mocked reponses to match the size of the url_list.

boottest.py

@@ -92,21 +92,21 @@ class TouchManifest(object):
             try:
                 response = urllib.urlopen(url)
                 if response.code == 200:
+                    # Only [re]create the manifest file if one was successfully
+                    # downloaded. This allows for an existing image to be used
+                    # if the download fails.
+                    path_dir = os.path.dirname(self.path)
+                    if not os.path.exists(path_dir):
+                        os.makedirs(path_dir)
+                    with open(self.path, 'w') as fp:
+                        fp.write(response.read())
+                    success = True
                     break
+
             except IOError as e:
                 print("W: [%s] - error connecting to %s: %s" % (
                         time.asctime(), self.path, e))
 
-        # Only [re]create the manifest file if one was successfully downloaded
-        # this allows for an existing image to be used if the download fails.
-        if response.code == 200:
-            path_dir = os.path.dirname(self.path)
-            if not os.path.exists(path_dir):
-                os.makedirs(path_dir)
-            with open(self.path, 'w') as fp:
-                fp.write(response.read())
-            success = True
-
         return success
 
     def _load(self):

tests/test_boottest.py

@@ -49,7 +49,10 @@ class TestTouchManifest(unittest.TestCase):
         self.addCleanup(shutil.rmtree, self.path)
         _p = mock.patch('urllib.urlopen')
         self.mocked_urlopen = _p.start()
-        self.mocked_urlopen.side_effect = [FakeResponse(code=404),]
+        self.mocked_urlopen.side_effect = [
+            FakeResponse(code=404),
+            FakeResponse(code=404),
+        ]
         self.addCleanup(_p.stop)
         self.fetch_retries_orig = boottest.FETCH_RETRIES
         def restore_fetch_retries():
@@ -90,7 +93,10 @@ class TestTouchManifest(unittest.TestCase):
         self.assertIn('foo', manifest)
 
     def test_fetch_exception(self):
-        self.mocked_urlopen.side_effect = [IOError("connection refused")]
+        self.mocked_urlopen.side_effect = [
+            IOError("connection refused"),
+            IOError("connection refused"),
+        ]
         manifest = boottest.TouchManifest('not-real', 'not-real')
         self.assertEqual(0, len(manifest._manifest))