settings: Add display setting for demoting inactive streams.

This adds a setting to control Zulip's default behavior of sorting to
bottom and graying out inactive streams.  The previous logic is still
the default "automatic", but this gives users more control.  See the
models.py comment for details.

Fixes #11524.

frontend_tests/node_tests/dispatch.js

@@ -607,6 +607,12 @@ var event_fixtures = {
         setting: true,
     },
 
+    update_display_settings__demote_inactive_streams: {
+        type: 'update_display_settings',
+        setting_name: 'demote_inactive_streams',
+        setting: 2,
+    },
+
     update_display_settings__translate_emoticons: {
         type: 'update_display_settings',
         setting_name: 'translate_emoticons',
@@ -1389,6 +1395,14 @@ with_overrides(function (override) {
     page_params.fluid_layout_width = false;
     dispatch(event);
     assert_same(page_params.fluid_layout_width, true);
+
+    global.with_stub(function (stub) {
+        event = event_fixtures.update_display_settings__demote_inactive_streams;
+        override('stream_list.update_streams_sidebar', stub.f);
+        page_params.demote_inactive_streams = 1;
+        dispatch(event);
+        assert_same(page_params.demote_inactive_streams, 2);
+    });
 });
 
 with_overrides(function (override) {

frontend_tests/node_tests/general.js

@@ -55,6 +55,8 @@ const denmark_stream = {
 // to make our tests more self-containted.
 
 zrequire('stream_data');
+set_global('i18n', global.stub_i18n);
+zrequire('settings_display');
 
 run_test('stream_data', () => {
     assert.equal(stream_data.get_sub_by_name('Denmark'), undefined);

frontend_tests/node_tests/stream_data.js

@@ -9,6 +9,7 @@ set_global('$', function () {
 
 set_global('blueslip', global.make_zblueslip());
 set_global('document', null);
+set_global('i18n', global.stub_i18n);
 global.stub_out_jquery();
 
 zrequire('color_data');
@@ -24,6 +25,7 @@ zrequire('Filter', 'js/filter');
 zrequire('MessageListData', 'js/message_list_data');
 zrequire('MessageListView', 'js/message_list_view');
 zrequire('message_list');
+zrequire('settings_display', 'js/settings_display');
 
 run_test('basics', () => {
     var denmark = {
@@ -291,15 +293,45 @@ run_test('is_active', () => {
 
     var sub;
 
+    page_params.demote_inactive_streams =
+        settings_display.demote_inactive_streams_values.automatic.code;
+
     sub = {name: 'pets', subscribed: false, stream_id: 111};
     stream_data.add_sub('pets', sub);
 
     assert(stream_data.is_active(sub));
 
-    stream_data.set_filter_out_inactives(true);
+    stream_data.subscribe_myself(sub);
+    assert(stream_data.is_active(sub));
+
+    stream_data.unsubscribe_myself(sub);
+    assert(stream_data.is_active(sub));
+
+    sub.pin_to_top = true;
+    assert(stream_data.is_active(sub));
+    sub.pin_to_top = false;
+
+    var opts = {
+        stream_id: 222,
+        message_id: 108,
+        topic_name: 'topic2',
+    };
+    topic_data.add_message(opts);
+
+    assert(stream_data.is_active(sub));
+
+    page_params.demote_inactive_streams =
+        settings_display.demote_inactive_streams_values.always.code;
+
+    sub = {name: 'pets', subscribed: false, stream_id: 111};
+    stream_data.add_sub('pets', sub);
 
     assert(!stream_data.is_active(sub));
 
+    sub.pin_to_top = true;
+    assert(stream_data.is_active(sub));
+    sub.pin_to_top = false;
+
     stream_data.subscribe_myself(sub);
     assert(stream_data.is_active(sub));
 
@@ -309,13 +341,29 @@ run_test('is_active', () => {
     sub = {name: 'lunch', subscribed: false, stream_id: 222};
     stream_data.add_sub('lunch', sub);
 
-    assert(!stream_data.is_active(sub));
+    assert(stream_data.is_active(sub));
+
+    topic_data.add_message(opts);
+
+    assert(stream_data.is_active(sub));
+
+    page_params.demote_inactive_streams =
+        settings_display.demote_inactive_streams_values.never.code;
+
+    sub = {name: 'pets', subscribed: false, stream_id: 111};
+    stream_data.add_sub('pets', sub);
+
+    assert(stream_data.is_active(sub));
+
+    stream_data.subscribe_myself(sub);
+    assert(stream_data.is_active(sub));
+
+    stream_data.unsubscribe_myself(sub);
+    assert(stream_data.is_active(sub));
+
+    sub.pin_to_top = true;
+    assert(stream_data.is_active(sub));
 
-    var opts = {
-        stream_id: 222,
-        message_id: 108,
-        topic_name: 'topic2',
-    };
     topic_data.add_message(opts);
 
     assert(stream_data.is_active(sub));
@@ -695,6 +743,7 @@ run_test('initialize', () => {
     }
 
     initialize();
+    page_params.demote_inactive_streams = 1;
     page_params.realm_notifications_stream_id = -1;
     stream_data.initialize();
     assert(!stream_data.is_filtering_inactives());

frontend_tests/node_tests/stream_list.js

@@ -18,6 +18,8 @@ zrequire('list_cursor');
 zrequire('stream_list');
 zrequire('topic_zoom');
 zrequire('ui');
+set_global('i18n', global.stub_i18n);
+zrequire('settings_display');
 
 stream_color.initialize();
 
@@ -33,10 +35,15 @@ set_global('keydown_util', {
     handle: noop,
 });
 
+set_global('page_params', {
+    is_admin: false,
+    realm_users: [],
+});
+
 run_test('create_sidebar_row', () => {
     // Make a couple calls to create_sidebar_row() and make sure they
     // generate the right markup as well as play nice with get_stream_li().
-
+    page_params.demote_inactive_streams = 1;
     var devel = {
         name: 'devel',
         stream_id: 100,

frontend_tests/node_tests/ui_init.js

@@ -121,6 +121,7 @@ zrequire('starred_messages');
 zrequire('user_status');
 zrequire('user_status_ui');
 zrequire('ui_init');
+zrequire('settings_display');
 
 set_global('$', global.make_zjquery());