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

@@ -92,20 +92,20 @@ class TouchManifest(object):
             try:
                 response = urllib.urlopen(url)
                 if response.code == 200:
-                    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:
+                    # 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))
 
         return success
 

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))