diff --git a/highfive/newpr.py b/highfive/newpr.py
index ba068a39..3d441f1f 100644
--- a/highfive/newpr.py
+++ b/highfive/newpr.py
@@ -53,13 +53,14 @@ def __init__(self, payload, config, config_dir=None):
         self.integration_user = config.github_username
         self.integration_token = config.github_token
 
-        self.repo_config = self.load_repo_config(config_dir)
+        self.config_dir = config_dir
+        self.repo_config = self.load_repo_config()
 
-    def load_repo_config(self, config_dir=None):
+    def load_repo_config(self):
         '''Load the repository configuration.'''
         (org, repo) = self.payload['repository', 'full_name'].split('/')
         try:
-            return self._load_json_file(os.path.join(org, repo) + '.json', config_dir)
+            return self._load_json_file(os.path.join(org, repo) + '.json')
         except IOError:
             raise UnsupportedRepoError
 
@@ -75,8 +76,9 @@ def run(self, event):
         else:
             return 'Unsupported webhook event.\n'
 
-    def _load_json_file(self, name, config_dir=None):
-        if not config_dir:
+    def _load_json_file(self, name):
+        config_dir = self.config_dir
+        if not self.config_dir:
             config_dir = os.path.join(os.path.dirname(__file__), 'configs')
 
         with open(os.path.join(config_dir, name)) as config:
diff --git a/highfive/tests/test_newpr.py b/highfive/tests/test_newpr.py
index 9cc45bd1..d8d6808e 100644
--- a/highfive/tests/test_newpr.py
+++ b/highfive/tests/test_newpr.py
@@ -84,7 +84,7 @@ def test_load_repo_config_supported(self, mock_load_json_file):
         m.stop_patchers()
         assert m.handler.load_repo_config() == {'a': 'config!'}
         mock_load_json_file.assert_called_once_with(
-            os.path.join('foo', 'blah.json'), None,
+            os.path.join('foo', 'blah.json'),
         )
 
     @mock.patch('highfive.newpr.HighfiveHandler._load_json_file')
@@ -99,7 +99,7 @@ def test_load_repo_config_unsupported(self, mock_load_json_file):
         with pytest.raises(newpr.UnsupportedRepoError):
             m.handler.load_repo_config()
         mock_load_json_file.assert_called_once_with(
-            os.path.join('foo', 'blah.json'), None
+            os.path.join('foo', 'blah.json'),
         )
 
 class TestNewPRGeneral(TestNewPR):