buttons/helper: Add support for topic narrow in handle_narrow().

Tests added.

tests/helper/test_helper.py

@@ -3,7 +3,7 @@
 import zulipterminal.helper
 from zulipterminal.helper import (
     canonicalize_color, classify_unread_counts, display_error_if_present,
-    index_messages, notify, powerset,
+    hash_util_decode, index_messages, notify, powerset,
 )
 
 
@@ -298,3 +298,16 @@ def test_display_error_if_present(mocker, response, footer_updated):
         set_footer_text.assert_called_once_with(response['msg'], 3)
     else:
         set_footer_text.assert_not_called()
+
+
+@pytest.mark.parametrize('quoted_string, expected_unquoted_string', [
+    ('(no.20topic)', '(no topic)'),
+    ('.3Cstrong.3Exss.3C.2Fstrong.3E', '<strong>xss</strong>'),
+    ('.23test-here.20.23T1.20.23T2.20.23T3', '#test-here #T1 #T2 #T3'),
+    ('.2Edot', '.dot'),
+    ('.3Aparty_parrot.3A', ':party_parrot:'),
+])
+def test_hash_util_decode(quoted_string, expected_unquoted_string):
+    return_value = hash_util_decode(quoted_string)
+
+    assert return_value == expected_unquoted_string

tests/ui/test_ui_tools.py

@@ -2797,3 +2797,37 @@ def test_handle_narrow_to_stream(self, mocker, stream_dict, link,
             assert self.controller.view.set_footer_text.called
             assert not self.controller.narrow_to_stream.called
             assert not self.controller.exit_popup.called
+
+    @pytest.mark.parametrize(['link', 'is_subscribed', 'stream_id',
+                              'stream_name', 'topic_name'], [
+        (SERVER_URL + '/#narrow/stream/1-Stream-1/topic/Test', True, 1,
+         'Stream 1', 'Test'),
+        (SERVER_URL + '/#narrow/stream/2-Stream-2/topic/Topic.20test', True, 2,
+         'Stream 2', 'Topic test'),
+        (SERVER_URL + '/#narrow/stream/4-Stream-4/topic/Test', False, 4, None,
+         None),
+    ])
+    def test_handle_narrow_to_topic(self, mocker, stream_dict, link,
+                                    is_subscribed, stream_id, stream_name,
+                                    topic_name):
+        self.controller.model.stream_dict = stream_dict
+        self.controller.view.set_footer_text = mocker.Mock()
+        self.controller.narrow_to_topic = mocker.Mock()
+        self.controller.exit_popup = mocker.Mock()
+        mocked_button = self.message_link_button(link=link)
+
+        mocked_button.handle_narrow()
+
+        assert mocked_button.stream_id == stream_id
+        if is_subscribed:
+            assert mocked_button.stream_name == stream_name
+            assert mocked_button.topic_name == topic_name
+            assert not self.controller.view.set_footer_text.called
+            assert self.controller.narrow_to_topic.called
+            assert self.controller.exit_popup.called
+        else:
+            assert not hasattr(mocked_button, 'stream_name')
+            assert not hasattr(mocked_button, 'topic_name')
+            assert self.controller.view.set_footer_text.called
+            assert not self.controller.narrow_to_topic.called
+            assert not self.controller.exit_popup.called

zulipterminal/helper.py

@@ -11,6 +11,7 @@
     Any, Callable, DefaultDict, Dict, FrozenSet, Iterable, List, Set, Tuple,
     TypeVar, Union,
 )
+from urllib.parse import unquote
 
 import lxml.html
 from mypy_extensions import TypedDict
@@ -618,3 +619,9 @@ def display_error_if_present(response: Dict[str, Any], controller: Any
                              ) -> None:
     if response['result'] == 'error' and hasattr(controller, 'view'):
         controller.view.set_footer_text(response['msg'], 3)
+
+
+def hash_util_decode(string: str) -> str:
+    # Acknowledge custom string replacements in zulip/zulip's
+    # zerver/lib/url_encoding.py before unquote.
+    return unquote(string.replace('.', '%').replace('%2E', '.'))

zulipterminal/ui_tools/buttons.py

@@ -3,6 +3,7 @@
 import urwid
 
 from zulipterminal.config.keys import is_command_key, keys_for_command
+from zulipterminal.helper import hash_util_decode
 from zulipterminal.urwid_types import urwid_Size
 
 
@@ -298,9 +299,8 @@ def handle_link(self, *_: Any) -> None:
 
     def handle_narrow(self) -> None:
         """
-        Handles stream narrow.
+        Handles stream and topic narrow.
         """
-        # TODO: Handle topic narrow.
         link_split = self.link.split('/')
 
         self.stream_id = int(link_split[5].split('-')[0])
@@ -313,7 +313,14 @@ def handle_narrow(self) -> None:
 
         self.stream_name = self.model.stream_dict[self.stream_id]['name']
 
-        if '/stream/' in self.link:
+        if '/topic/' in self.link:
+            encoded_topic = link_split[7]
+            self.topic_name = hash_util_decode(encoded_topic)
+            assert hasattr(self, 'stream_id')
+            assert hasattr(self, 'stream_name')
+            assert hasattr(self, 'topic_name')
+            self.controller.narrow_to_topic(self)
+        elif '/stream/' in self.link:
             assert hasattr(self, 'stream_id')
             assert hasattr(self, 'stream_name')
             self.controller.narrow_to_stream(self)