Add simple test for extracting error title

CURA-7959

plugins/DigitalLibrary/src/DFFileExportAndUploadManager.py

@@ -2,6 +2,7 @@
 # Cura is released under the terms of the LGPLv3 or higher.
 import json
 import threading
+from json import JSONDecodeError
 from typing import List, Dict, Any, Callable, Union, Optional
 
 from PyQt5.QtCore import QUrl
@@ -271,7 +272,11 @@ class DFFileExportAndUploadManager:
     def extractErrorTitle(reply_body: Optional[str]) -> str:
         error_title = ""
         if reply_body:
-            reply_dict = json.loads(reply_body)
+            try:
+                reply_dict = json.loads(reply_body)
+            except JSONDecodeError:
+                Logger.logException("w", "Unable to extract title from reply body")
+                return error_title
             if "errors" in reply_dict and len(reply_dict["errors"]) >= 1 and "title" in reply_dict["errors"][0]:
                 error_title = reply_dict["errors"][0]["title"]
         return error_title

plugins/DigitalLibrary/tests/TestDFFileExportAndUploadManager.py

@@ -0,0 +1,32 @@
+from unittest.mock import MagicMock, patch
+
+import pytest
+from src.DFFileExportAndUploadManager import DFFileExportAndUploadManager
+
+
+@pytest.fixture
+def upload_manager():
+    file_handler = MagicMock(name = "file_handler")
+    node = MagicMock(name = "SceneNode")
+    application = MagicMock(name = "CuraApplication")
+    with patch("cura.CuraApplication.CuraApplication.getInstance", MagicMock(return_value=application)):
+        return DFFileExportAndUploadManager(file_handlers = {"test": file_handler},
+                                            nodes = [node],
+                                            library_project_id = "test_library_project_id",
+                                            library_project_name = "test_library_project_name",
+                                            file_name = "file_name",
+                                            formats = ["3mf"],
+                                            on_upload_error = MagicMock(),
+                                            on_upload_success = MagicMock(),
+                                            on_upload_finished = MagicMock(),
+                                            on_upload_progress = MagicMock())
+
+
+@pytest.mark.parametrize("input,expected_result",
+                        [("", ""),
+                         ("invalid json! {}", ""),
+                         ("{\"errors\": [{}]}", ""),
+                         ("{\"errors\": [{\"title\": \"some title\"}]}", "some title")])
+def test_extractErrorTitle(upload_manager, input, expected_result):
+    assert upload_manager.extractErrorTitle(input) == expected_result
+

plugins/DigitalLibrary/tests/TestDigitalLibraryApiClient.py

@@ -18,6 +18,7 @@ def pagination_manager():
     manager = MagicMock(name = "Mocked Pagination Manager")
     return manager
 
+
 @pytest.fixture
 def api_client(application, pagination_manager):
     api_client = DigitalFactoryApiClient(application, MagicMock())