model/boxes: Allow users to post stream messages without a topic.

This follows the convention used by other Zulip clients to
automatically post a message without a topic to a topic named '(no topic)'.

Also, while editing such topics, the topic name would be shown as empty
to the user, even though in reality it is not. This is done to make it
easier for users to set names to empty topics, as well as to follow the
behaviour of other clients.

Tests amended.

Fixes #754.

Author: kaustubh-nair

tests/model/test_model.py

@@ -395,15 +395,26 @@ def test_send_private_message(self, mocker, model,
         ({'result': 'success'}, True),
         ({'result': 'some_failure'}, False),
     ])
+    @pytest.mark.parametrize(['topic_set_by_user',
+                             'topic_sent_to_server'], [
+        ('bar', 'bar'),
+        ('', '(no topic)'),
+    ], ids=[
+        'message_with_topic',
+        'message_with_no_topic',
+    ])
     def test_send_stream_message(self, mocker, model,
                                  response, return_value,
-                                 content="hi!",
-                                 stream="foo", topic="bar"):
+                                 topic_sent_to_server,
+                                 topic_set_by_user, content="hi!",
+                                 stream="foo"):
         self.client.send_message = mocker.Mock(return_value=response)
 
-        result = model.send_stream_message(stream, topic, content)
+        result = model.send_stream_message(stream, topic_set_by_user,
+                                           content)
 
-        req = dict(type='stream', to=stream, subject=topic, content=content)
+        req = dict(type='stream', to=stream, subject=topic_sent_to_server,
+                   content=content)
         self.client.send_message.assert_called_once_with(req)
 
         assert result == return_value
@@ -433,16 +444,22 @@ def test_update_private_message(self, mocker, model,
         ({'result': 'success'}, True),
         ({'result': 'some_failure'}, False),
     ])
+    @pytest.mark.parametrize('topic_set_by_user, topic_sent_to_server', [
+        ('bar', 'bar'),
+        ('', '(no topic)'),
+    ], ids=[
+        'message_with_topic',
+        'message_with_no_topic',
+    ])
     def test_update_stream_message(self, mocker, model,
                                    response, return_value,
-                                   content="hi!",
-                                   subject='Hello',
-                                   msg_id=1):
+                                   topic_set_by_user, topic_sent_to_server,
+                                   content="hi!", msg_id=1):
         self.client.update_message = mocker.Mock(return_value=response)
 
-        result = model.update_stream_message(subject, msg_id, content)
+        result = model.update_stream_message(topic_set_by_user, msg_id, content)
 
-        req = dict(subject=subject, propagate_mode="change_one",
+        req = dict(subject=topic_sent_to_server, propagate_mode="change_one",
                    message_id=msg_id, content=content)
         self.client.update_message.assert_called_once_with(req)
 

zulipterminal/model.py

@@ -310,6 +310,8 @@ def send_private_message(self, recipients: str,
 
     def send_stream_message(self, stream: str, topic: str,
                             content: str) -> bool:
+        if topic == '':
+            topic = '(no topic)'
         request = {
             'type': 'stream',
             'to': stream,
@@ -331,6 +333,8 @@ def update_private_message(self, msg_id: int, content: str) -> bool:
 
     def update_stream_message(self, topic: str, msg_id: int,
                               content: str) -> bool:
+        if topic == '':
+            topic = '(no topic)'
         request = {
             "message_id": msg_id,
             "content": content,

zulipterminal/ui_tools/boxes.py

@@ -75,6 +75,8 @@ def stream_box_view(self, caption: str='', title: str='') -> None:
             caption="Stream:  ",
             edit_text=caption
         )
+        if title == '(no topic)':
+            title = ''
         self.title_write_box = ReadlineEdit(caption="Topic:  ",
                                             edit_text=title)