model: Report error details from failed initial API calls.

Given failed calls now provide a textual reason, this information can be
passed to returned exceptions, and ultimately to the user.

This change applies to the initial connection only.

Since ZulipError error texts are now returned, as well as responses from
successful network calls which fail at the server, a test case is added
for each.

Author: neiljp

tests/model/test_model.py

@@ -3,6 +3,7 @@
 from typing import Any
 
 import pytest
+from zulip import ZulipError
 
 from zulipterminal.helper import initial_index, powerset
 from zulipterminal.model import Model, ServerConnectionFailure
@@ -67,6 +68,49 @@ def test_init(self, model, initial_data, user_profile):
         self.classify_unread_counts.assert_called_once_with(model)
         assert model.unread_counts == []
 
+    def test_init_InvalidAPIKey_response(self, mocker, initial_data):
+        # Both network calls indicate the same response
+        mocker.patch('zulipterminal.model.Model.get_messages',
+                     return_value='Invalid API key')
+        mocker.patch('zulipterminal.model.Model._register_desired_events',
+                     return_value='Invalid API key')
+
+        mocker.patch('zulipterminal.model.Model.get_all_users',
+                     return_value=[])
+        mocker.patch('zulipterminal.model.Model.'
+                     '_stream_info_from_subscriptions',
+                     return_value=({}, set(), [], []))
+        self.classify_unread_counts = mocker.patch(
+            'zulipterminal.model.classify_unread_counts',
+            return_value=[])
+
+        with pytest.raises(ServerConnectionFailure) as e:
+            model = Model(self.controller)
+
+        assert str(e.value) == 'Invalid API key (get_messages, register)'
+
+    def test_init_ZulipError_exception(self, mocker, initial_data,
+                                       exception_text="X"):
+        # Both network calls fail, resulting in exceptions
+        mocker.patch('zulipterminal.model.Model.get_messages',
+                     side_effect=ZulipError(exception_text))
+        mocker.patch('zulipterminal.model.Model._register_desired_events',
+                     side_effect=ZulipError(exception_text))
+
+        mocker.patch('zulipterminal.model.Model.get_all_users',
+                     return_value=[])
+        mocker.patch('zulipterminal.model.Model.'
+                     '_stream_info_from_subscriptions',
+                     return_value=({}, set(), [], []))
+        self.classify_unread_counts = mocker.patch(
+            'zulipterminal.model.classify_unread_counts',
+            return_value=[])
+
+        with pytest.raises(ServerConnectionFailure) as e:
+            model = Model(self.controller)
+
+        assert str(e.value) == exception_text + ' (get_messages, register)'
+
     def test_register_initial_desired_events(self, mocker, initial_data):
         mocker.patch('zulipterminal.model.Model.get_messages',
                      return_value='')

zulipterminal/model.py

@@ -1,11 +1,11 @@
 import json
 import time
-from collections import OrderedDict
+from collections import OrderedDict, defaultdict
 from concurrent.futures import Future, ThreadPoolExecutor, wait
 from threading import Thread
 from typing import (
-    Any, Callable, Dict, FrozenSet, Iterable, List, Optional, Set, Tuple,
-    Union,
+    Any, Callable, DefaultDict, Dict, FrozenSet, Iterable, List, Optional, Set,
+    Tuple, Union,
 )
 from urllib.parse import urlparse
 
@@ -441,8 +441,15 @@ def _update_initial_data(self) -> None:
             self.user_full_name = self.initial_data['full_name']
             self.server_name = self.initial_data['realm_name']
         else:
-            failures = [name for name, result in results.items() if result]
-            raise ServerConnectionFailure(", ".join(failures))
+            failures = defaultdict(list)  # type: DefaultDict[str, List[str]]
+            for name, result in results.items():
+                if result:
+                    failures[result].append(name)
+            failure_text = [
+                "{} ({})".format(error, ", ".join(sorted(calls)))
+                for error, calls in failures.items()
+            ]
+            raise ServerConnectionFailure(", ".join(failure_text))
 
     def get_all_users(self) -> List[Dict[str, Any]]:
         # Dict which stores the active/idle status of users (by email)