test: add tests for stream chat flutter (#335)

* feat: Added tests

* feat: Added header test

* feat: Added new tests

* fix

* feat: Added test, fmt

* feat: Added delete test

* added system and unread ind tests

* fix: analysis

* added new tests

* fix: analysis

* added tests

* add attachment actions modal tests

* fix analysis

* fix analysis

* add backbutton tests

* fix analysis

* increase timeout

* add channelheader tests

* add infotile tests

* add reactions modal and channel unread indicator tests

* add golden test for reaction bubble

* add dark tests

* add system message golden

* add deletd message golden

* add message action modal tests

* update goldens

* update workflow runner

* update goldens

* remove channel unread indicator in favor of unread indicator

* move file and media screen to sample app

* add channel image tesst

* add channel_list_header test

* add thread_header test

* bump up test threashold

* fix review

Co-authored-by: Salvatore Giordano <[email protected]>

packages/stream_chat_flutter/test/src/channel_preview_test.dart

@@ -15,6 +15,7 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
+      when(channel.cid).thenReturn('cid');
       when(client.state).thenReturn(clientState);
       when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
       when(channel.lastMessageAt).thenReturn(lastMessageAt);
@@ -28,6 +29,9 @@ void main() {
       when(channel.extraData).thenReturn({
         'name': 'test name',
       });
+      when(clientState.channels).thenReturn({
+        channel.cid: channel,
+      });
       when(channelState.unreadCount).thenReturn(1);
       when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
       when(channelState.membersStream).thenAnswer((i) => Stream.value([