core/views: Show server version and feature level in about popup.

The server version and the feature level are shown under a 'Server'
category.

Note: Feature level is only shown in the popup when it is present.

Test amended and added to check whether feature level is added to the
about menu based on its availability.

Fixes #616.

Author: preetmishra

tests/ui/test_ui_tools.py

@@ -17,6 +17,7 @@
     ModListWalker, MsgInfoView, PopUpConfirmationView, PopUpView,
     RightColumnView, StreamInfoView, StreamsView, TopicsView, UsersView,
 )
+from zulipterminal.version import MINIMUM_SUPPORTED_SERVER_VERSION
 
 
 VIEWS = "zulipterminal.ui_tools.views"
@@ -1246,8 +1247,11 @@ def mock_external_classes(self, mocker):
         mocker.patch.object(self.controller, 'maximum_popup_dimensions',
                             return_value=(64, 64))
         mocker.patch(VIEWS + '.urwid.SimpleFocusListWalker', return_value=[])
+        server_version, server_feature_level = MINIMUM_SUPPORTED_SERVER_VERSION
         self.about_view = AboutView(self.controller, 'About',
-                                    zt_version='0.5.1+git')
+                                    zt_version='0.5.1+git',
+                                    server_version=server_version,
+                                    server_feature_level=server_feature_level)
 
     @pytest.mark.parametrize('key', {*keys_for_command('GO_BACK'),
                                      *keys_for_command('ABOUT')})
@@ -1270,6 +1274,19 @@ def test_keypress_navigation(self, mocker,
         self.about_view.keypress(size, key)
         super_keypress.assert_called_once_with(size, expected_key)
 
+    def test_feature_level_content(self, mocker, zulip_version):
+        self.controller = mocker.Mock()
+        mocker.patch.object(self.controller, 'maximum_popup_dimensions',
+                            return_value=(64, 64))
+        mocker.patch(VIEWS + '.urwid.SimpleFocusListWalker', return_value=[])
+        server_version, server_feature_level = zulip_version
+        about_view = AboutView(self.controller, 'About', zt_version='0.5.1',
+                               server_version=server_version,
+                               server_feature_level=server_feature_level)
+        assert len(about_view.feature_level_content) == (
+            1 if server_feature_level else 0
+        )
+
 
 class TestPopUpConfirmationView:
     @pytest.fixture

zulipterminal/core.py

@@ -148,7 +148,11 @@ def popup_with_message(self, text: str, width: int) -> None:
         self.show_pop_up(NoticeView(self, text, width, "NOTICE"))
 
     def show_about(self) -> None:
-        self.show_pop_up(AboutView(self, 'About', zt_version=ZT_VERSION))
+        self.show_pop_up(
+            AboutView(self, 'About', zt_version=ZT_VERSION,
+                      server_version=self.model.server_version,
+                      server_feature_level=self.model.server_feature_level)
+        )
 
     def search_messages(self, text: str) -> None:
         # Search for a text in messages

zulipterminal/ui_tools/views.py

@@ -879,10 +879,17 @@ def __init__(self, controller: Any,
 
 
 class AboutView(PopUpView):
-    def __init__(self, controller: Any, title: str, *,
-                 zt_version: str) -> None:
+    def __init__(self, controller: Any, title: str, *, zt_version: str,
+                 server_version: str,
+                 server_feature_level: Optional[int]) -> None:
+        self.feature_level_content = (
+            [('Feature level', str(server_feature_level))]
+            if server_feature_level else []
+        )
         contents = [
             ('Application', [('Zulip Terminal', zt_version)]),
+            ('Server', [('Version', server_version)]
+             + self.feature_level_content),
         ]
 
         popup_width, column_widths = self.calculate_table_widths(contents,