bugfix: boxes: Allow message body editing when limit doesn't exist.

This commit fixes a bug that doesn't let users edit the message body
when the `realm_message_content_edit_limit_seconds` sent by the server
is 0 for a realm. Prior to this commit, this configuration of 0 was
treated as a complete restriction against message body editing, while
the configuration actually signified no limit in message body editing.

Fixes #1034.

Author: prah23

tests/ui/test_ui_tools.py

@@ -1901,28 +1901,32 @@ def test_keypress_STREAM_MESSAGE(self, mocker, msg_box, widget_size,
     @pytest.mark.parametrize(['to_vary_in_each_message',
                               'realm_editing_allowed',
                               'msg_body_edit_enabled',
+                              'msg_body_edit_limit',
                               'expect_editing_to_succeed'], [
-        ({'sender_id': 2, 'timestamp': 45}, True, True, False),
-        ({'sender_id': 1, 'timestamp': 1}, True, False, True),
-        ({'sender_id': 1, 'timestamp': 45}, False, True, False),
-        ({'sender_id': 1, 'timestamp': 45}, True, True, True),
+        ({'sender_id': 2, 'timestamp': 45}, True, True, 60, False),
+        ({'sender_id': 1, 'timestamp': 1}, True, False, 60, True),
+        ({'sender_id': 1, 'timestamp': 45}, False, True, 60, False),
+        ({'sender_id': 1, 'timestamp': 45}, True, True, 60, True),
+        ({'sender_id': 1, 'timestamp': 1}, True, True, 0, True),
     ], ids=['msg_sent_by_other_user',
             'topic_edit_only_after_time_limit',
             'editing_not_allowed',
-            'all_conditions_met'])
+            'all_conditions_met',
+            'no_msg_body_edit_limit'])
     def test_keypress_EDIT_MESSAGE(self, mocker, message_fixture, widget_size,
                                    expect_editing_to_succeed,
                                    to_vary_in_each_message,
                                    realm_editing_allowed,
                                    msg_body_edit_enabled,
+                                   msg_body_edit_limit,
                                    key):
         varied_message = dict(message_fixture, **to_vary_in_each_message)
         msg_box = MessageBox(varied_message, self.model, message_fixture)
         size = widget_size(msg_box)
         msg_box.model.user_id = 1
         msg_box.model.initial_data = {
             'realm_allow_message_editing': realm_editing_allowed,
-            'realm_message_content_edit_limit_seconds': 60,
+            'realm_message_content_edit_limit_seconds': msg_body_edit_limit,
         }
         msg_box.model.client.get_raw_message.return_value = {
             'raw_content': "Edit this message"
@@ -1931,9 +1935,10 @@ def test_keypress_EDIT_MESSAGE(self, mocker, message_fixture, widget_size,
         write_box.msg_edit_id = None
         write_box.msg_body_edit_enabled = None
         mocker.patch("zulipterminal.ui_tools.boxes.time", return_value=100)
-        # private messages cannot be edited after time-limit.
+        # private messages cannot be edited after time-limit, if there is one.
         if (varied_message['type'] == 'private'
-                and varied_message['timestamp'] == 1):
+                and varied_message['timestamp'] == 1
+                and msg_body_edit_limit > 0):
             expect_editing_to_succeed = False
 
         msg_box.keypress(size, key)

zulipterminal/ui_tools/boxes.py

@@ -1518,23 +1518,26 @@ def keypress(self, size: urwid_Size, key: str) -> Optional[str]:
                     " Editing sent message is disabled.", 3)
                 return key
             # Check if message is still editable, i.e. within
-            # the time limit.
-            time_since_msg_sent = time() - self.message['timestamp']
-            edit_time_limit = self.model.initial_data[
-                    'realm_message_content_edit_limit_seconds']
+            # the time limit. A limit of 0 signifies no limit
+            # on message body editing.
             msg_body_edit_enabled = True
-            if time_since_msg_sent >= edit_time_limit:
-                if self.message['type'] == 'private':
-                    self.model.controller.view.set_footer_text(
-                            " Time Limit for editing the message has"
-                            " been exceeded.", 3)
-                    return key
-                elif self.message['type'] == 'stream':
-                    self.model.controller.view.set_footer_text(
-                            " Only topic editing allowed."
-                            " Time Limit for editing the message body has"
-                            " been exceeded.", 3)
-                    msg_body_edit_enabled = False
+            if self.model.initial_data[
+                    'realm_message_content_edit_limit_seconds'] > 0:
+                time_since_msg_sent = time() - self.message['timestamp']
+                edit_time_limit = self.model.initial_data[
+                        'realm_message_content_edit_limit_seconds']
+                if time_since_msg_sent >= edit_time_limit:
+                    if self.message['type'] == 'private':
+                        self.model.controller.view.set_footer_text(
+                                " Time Limit for editing the message has"
+                                " been exceeded.", 3)
+                        return key
+                    elif self.message['type'] == 'stream':
+                        self.model.controller.view.set_footer_text(
+                                " Only topic editing allowed."
+                                " Time Limit for editing the message body has"
+                                " been exceeded.", 3)
+                        msg_body_edit_enabled = False
 
             if self.message['type'] == 'private':
                 self.keypress(size, 'enter')