views: Improve stream and topic search to do a substring search.

Improved stream/topic search to find if the query is a substring
of any stream/topic instead of just trying to find if the query
is at the start of any stream/topic.

Tests amended.

Fixes #509.

Author: preetmishra

tests/ui/test_ui_tools.py

@@ -410,17 +410,26 @@ def test_init(self, mocker, stream_view):
             stream_view, 'SEARCH_STREAMS', stream_view.update_streams)
 
     @pytest.mark.parametrize('new_text, expected_log', [
-        ('f', ['FOO', 'foo', 'fan']),
-        ('foo', ['FOO', 'foo']),
-        ('FOO', ['FOO', 'foo']),
+        ('f', ['FOO', 'FOOBAR', 'foo', 'fan']),
+        ('a', ['FOOBAR', 'fan', 'bar']),
+        ('bar', ['FOOBAR', 'bar']),
+        ('foo', ['FOO', 'FOOBAR', 'foo']),
+        ('FOO', ['FOO', 'FOOBAR', 'foo']),
+        ('test', ['test here']),
+        ('here', ['test here']),
     ])
     def test_update_streams(self, mocker, stream_view, new_text, expected_log):
+        stream_names = [
+            'FOO', 'FOOBAR', 'foo', 'fan',
+            'boo', 'BOO', 'bar', 'test here',
+        ]
         self.view.controller.editor_mode = True
         new_text = new_text
         search_box = "SEARCH_BOX"
         stream_view.streams_btn_list = [
-            mocker.Mock(stream_name=stream_name) for stream_name in [
-                'FOO', 'foo', 'fan', 'boo', 'BOO']]
+            mocker.Mock(stream_name=stream_name)
+            for stream_name in stream_names
+        ]
         stream_view.update_streams(search_box, new_text)
         assert [stream.stream_name for stream in stream_view.log
                 ] == expected_log
@@ -521,17 +530,26 @@ def test_init(self, mocker, topic_view):
                                                   topic_view.topic_search_box])
 
     @pytest.mark.parametrize('new_text, expected_log', [
-        ('f', ['FOO', 'foo', 'fan']),
-        ('foo', ['FOO', 'foo']),
-        ('FOO', ['FOO', 'foo']),
+        ('f', ['FOO', 'FOOBAR', 'foo', 'fan']),
+        ('a', ['FOOBAR', 'fan', 'bar']),
+        ('bar', ['FOOBAR', 'bar']),
+        ('foo', ['FOO', 'FOOBAR', 'foo']),
+        ('FOO', ['FOO', 'FOOBAR', 'foo']),
+        ('(no', ['(no topic)']),
+        ('topic', ['(no topic)']),
     ])
     def test_update_topics(self, mocker, topic_view, new_text, expected_log):
+        topic_names = [
+            'FOO', 'FOOBAR', 'foo', 'fan',
+            'boo', 'BOO', 'bar', '(no topic)',
+        ]
         self.view.controller.editor_mode = True
         new_text = new_text
         search_box = "SEARCH_BOX"
         topic_view.topics_btn_list = [
-            mocker.Mock(topic_name=topic_name) for topic_name in [
-                'FOO', 'foo', 'fan', 'boo', 'BOO']]
+            mocker.Mock(topic_name=topic_name)
+            for topic_name in topic_names
+        ]
         topic_view.update_topics(search_box, new_text)
         assert [topic.topic_name for topic in topic_view.log
                 ] == expected_log

zulipterminal/ui_tools/views.py

@@ -270,10 +270,11 @@ def update_streams(self, search_box: Any, new_text: str) -> None:
         # wait for any previously started search to finish to avoid
         # displaying wrong stream list.
         with self.search_lock:
+            new_text = new_text.lower()
             streams_display = [
                 stream
                 for stream in self.streams_btn_list.copy()
-                if stream.stream_name.lower().startswith(new_text.lower())
+                if new_text in stream.stream_name.lower()
             ]
             self.log.clear()
             self.log.extend(streams_display)
@@ -334,10 +335,11 @@ def update_topics(self, search_box: Any, new_text: str) -> None:
         # wait for any previously started search to finish to avoid
         # displaying wrong topics list.
         with self.search_lock:
+            new_text = new_text.lower()
             topics_to_display = [
                 topic
                 for topic in self.topics_btn_list.copy()
-                if topic.topic_name.lower().startswith(new_text.lower())
+                if new_text in topic.topic_name.lower()
             ]
             self.log.clear()
             self.log.extend(topics_to_display)