model/views: Add method to regularly update state markers in messages.

This commit:
 * introduces asynch method `update_msg_box_presence_markers` in middle
   column view class. It would be responsible for rendering the status
   icons (if present) in message boxes.
 * adds presence renderer function to the handler `start_presence_updates`.
   This way, the method `update_msg_box_presence_markers` is called every
   minute.

The function `update_msg_box_presence_markers` uses existing model method
`_update_rendered_view` to update the message box (if required).

Tests added and amended.

Fixes zulip#896.

Author: Ezio-Sarthak

tests/ui/test_ui_tools.py

@@ -5,7 +5,7 @@
 import pytz
 from bs4 import BeautifulSoup
 from pytest import param as case
-from urwid import Columns, Divider, Padding, Text
+from urwid import AttrMap, Columns, Divider, Padding, Text
 
 from zulipterminal.config.keys import keys_for_command
 from zulipterminal.config.symbols import (
@@ -814,7 +814,7 @@ class TestMiddleColumnView:
     @pytest.fixture(autouse=True)
     def mock_external_classes(self, mocker):
         mocker.patch(VIEWS + ".MessageView", return_value="MSG_LIST")
-        self.model = mocker.Mock()
+        self.model = mocker.MagicMock()
         self.view = mocker.Mock()
         self.write_box = mocker.Mock()
         self.search_box = mocker.Mock()
@@ -887,6 +887,47 @@ def test_get_next_unread_pm_no_unread(self, mid_col_view):
         assert return_value is None
         assert mid_col_view.last_unread_pm is None
 
+    @pytest.mark.parametrize('message', [
+        {
+            'id': 4,
+            'type': 'stream',
+            'display_recipient': 'Verona',
+            'stream_id': 5,
+            'subject': 'Test topic',
+            'is_me_message': True,
+            'flags': [],
+            'content': '',
+            'reactions': [],
+            'sender_full_name': 'Human 1',  # this message name
+            'timestamp': 1532103879,
+        }
+    ])
+    @pytest.mark.parametrize('differences, header_needed, update_required', [
+        ({'subject': 'Test topic 2'}, True, True),
+        ({}, False, False),
+        ({'sender_full_name': 'Human 2'}, False, True),
+        ({'timestamp': 1532103869}, False, False),
+    ], ids=[
+        'recipient_header_present',
+        'recipient_header_not_present',
+        'content_header_present',
+        'content_header_not_present',
+    ])
+    def test_update_msg_box_presence_markers(self, mid_col_view, message,
+                                             update_required, mocker,
+                                             differences, header_needed):
+        last_msg = dict(message, **differences)
+
+        msg_box = MessageBox(message, mid_col_view.model, last_msg)
+
+        mid_col_view.body = mocker.Mock()
+        mocker.patch.object(mid_col_view.body, 'log',
+                            [AttrMap(msg_box, None)])
+
+        mid_col_view.update_msg_box_presence_markers()
+
+        assert self.model._update_rendered_view.called == update_required
+
     @pytest.mark.parametrize('key', keys_for_command('GO_BACK'))
     def test_keypress_GO_BACK(self, mid_col_view, mocker, key, widget_size):
         size = widget_size(mid_col_view)

zulipterminal/model.py

@@ -345,6 +345,8 @@ def _start_presence_updates(self) -> None:
                 if hasattr(self.controller, 'view'):
                     self.controller.view.users_view.update_user_list(
                         user_list=self.users)
+                    (self.controller.view.middle_column
+                        .update_msg_box_presence_markers())
             time.sleep(60)
 
     @asynch

zulipterminal/ui_tools/views.py

@@ -530,6 +530,25 @@ def get_next_unread_pm(self) -> Optional[int]:
             return pm
         return None
 
+    @asynch
+    def update_msg_box_presence_markers(self) -> None:
+        for msg_btn in self.body.log:
+            msg_box = msg_btn.original_widget
+
+            if msg_box.need_recipient_header():
+                is_sender_header = (msg_box[1][1].text != ' ')
+
+            # Content header is not None
+            elif isinstance(msg_box[0][1], urwid.Text):
+                is_sender_header = (msg_box[0][1].text != ' ')
+
+            # Content header is None
+            else:
+                is_sender_header = False
+
+            if is_sender_header:
+                self.model._update_rendered_view(msg_box.message['id'])
+
     def keypress(self, size: urwid_Size, key: str) -> Optional[str]:
         if is_command_key('GO_BACK', key):
             self.header.keypress(size, 'esc')