Gracefully handle server not found (#397)

* Gracefully handle server not found

* add test for server not found

jhub_apps/hub_client/hub_client.py

@@ -146,9 +146,9 @@ def start_server(self, username, servername):
         else:
             # Get named server
             server = self.get_server(username, servername)
-            user_options = server["user_options"]
             if not server:
                 return None
+            user_options = server["user_options"]
         url = f"/users/{username}/servers/{servername}"
         data = {"name": servername, **user_options}
         r = requests.post(API_URL + url, headers=self._headers(), json=data)

jhub_apps/tests/tests_unit/test_api.py

@@ -46,6 +46,19 @@ def test_api_get_server(get_user, client):
     assert response.json() == server_data["panel-app"]
 
 
+@patch.object(HubClient, "get_user")
+def test_api_get_server_not_found(get_user, client):
+    server_data = {"panel-app": {}}
+    get_users_response = {'name': 'aktech', 'servers': server_data}
+    get_user.return_value = get_users_response
+    response = client.get("/server/panel-app-not-found")
+    get_user.assert_called_once_with()
+    assert response.status_code == 404
+    assert response.json() == {
+        'detail': "server 'panel-app-not-found' not found",
+    }
+
+
 @patch.object(HubClient, "create_server")
 def test_api_create_server(create_server, client):
     from jhub_apps.service.models import UserOptions