views: Show author name in EditHistoryView.

Tests added.

Author: preetmishra

tests/ui/test_ui_tools.py

@@ -1224,13 +1224,14 @@ def test_keypress_navigation(self, mocker,
 
 class TestEditHistoryView:
     @pytest.fixture(autouse=True)
-    def mock_external_classes(self, mocker, message_fixture,
+    def mock_external_classes(self, mocker, message_fixture, users_fixture,
                               message_history_fixture):
         self.controller = mocker.Mock()
         self.controller.model.get_message_history = (
             mocker.Mock(return_value='')
         )
         message_fixture['message_history'] = message_history_fixture
+        self.controller.view.users = users_fixture
         mocker.patch(VIEWS + '.urwid.SimpleFocusListWalker', return_value=[])
         self.edit_history_view = EditHistoryView(self.controller,
                                                  message_fixture)
@@ -1241,6 +1242,12 @@ def test_init(self, mocker, message_fixture):
         (self.controller.model.get_message_history.
          assert_called_once_with(message_fixture))
 
+    @pytest.mark.parametrize('user_id, full_name', [
+        (5140, 'Foo Foo'), (11, 'Human 1'), (12, 'Human 2')])
+    def test_get_author(self, user_id, full_name):
+        result = self.edit_history_view.get_author(user_id)
+        assert result == full_name
+
     def test_keypress_exit_popup_any_key(self):
         key = 'a'
         size = (200, 20)

zulipterminal/ui_tools/views.py

@@ -952,7 +952,8 @@ def __init__(self, controller: Any, msg: Any) -> None:
                     self.widgets.append(self.build_pile(snapshot, 'Current'))
                     continue
                 elif index == 0:
-                    self.widgets.append(self.build_pile(snapshot, 'Original'))
+                    self.widgets.append(self.build_pile(snapshot, 'Original',
+                                                        'Posted'))
                 else:
                     self.widgets.append(self.build_pile(snapshot))
                 # Add a blank line after an edit block/pile.
@@ -967,27 +968,45 @@ def __init__(self, controller: Any, msg: Any) -> None:
         super().__init__(controller, self.widgets, 'MSG_INFO')
 
     def build_pile(self, snapshot: Dict[str, Any], tag: str='',
-                   ) -> Any:
+                   author_prefix: str='Edited') -> Any:
         timestamp = time.ctime(snapshot['timestamp'])[:-5]
+        author = self.get_author(snapshot['user_id'])
         topic = snapshot['topic']
 
         if 'prev_topic' in snapshot and topic != snapshot['prev_topic']:
             topic += ' (updated from {})'.format(snapshot['prev_topic'])
+            if 'prev_content' in snapshot:
+                author_prefix += ' and Topic updated'
+            else:
+                author_prefix = 'Topic updated'
 
         header = urwid.Columns([
                 urwid.Text(('edit_topic', topic)),
                 (19, urwid.Text(('edit_time', timestamp))),
             ], dividechars=2,
         )
         subheader = urwid.Columns([
+                urwid.Text(('edit_author',
+                            '{} by {}'.format(author_prefix, author))),
                 (18, urwid.Text(('edit_tag', '({} Version)'.format(tag) if tag
-                                else ''))),
+                                else ''), align='right')),
             ], dividechars=2,
         )
         message = urwid.Text(snapshot['content'])
         return urwid.Pile([urwid.AttrWrap(header, 'popup_contrast'), subheader,
                            message])
 
+    def get_author(self, user_id: int) -> str:
+        if self.msg['sender_id'] == user_id:
+            return self.msg['sender_full_name']
+        else:
+            for user in self.controller.view.users:
+                if user['user_id'] == user_id:
+                    return user['full_name']
+        # NOTE: This return statement is redundant and only put here to pass
+        # mypy as a user with `user_id` will always exist.
+        return ''
+
     def keypress(self, size: urwid_Size, key: str) -> str:
         if (is_command_key('GO_BACK', key)
                 or is_command_key('EDIT_HISTORY', key)):