left-sidebar: Sort pinned streams by lowercase stream name.

The pinned streams were sorted in alphabetic order (i.e. Verona appears
before devel). The reason is that after we plucked pinned streams out from
stream_data.subscribed_streams(), we didn't sort them again, so they
remained in the alphabetic order used in stream_data.

However, we did sort unpinned streams explicitly by using custom compare
function in stream_list.js (by default sort by lowercase stream name,
but when there are more than 40 subscribed streams, sort active streams
first). That's why this issue only relates to pinned streams.

Changes were made to sort pinned streams by lowercase stream name, always,
whether they are active or not (different from unpinned streams).

Tests were added to ensure this overall sort order is correct, i.e.

1. pinned streams are always sorted by lowercase stream name.
2. pinned streams are always before unpinned streams.
3. unpinned streams are sorted by lowercase stream name, if there are more
   than 40 subscribed streams, sort active streams at the top, among active
   and inactive streams, still sorted by lowercase stream name.

Fixes #3701

frontend_tests/node_tests/stream_list.js

@@ -2,6 +2,7 @@ global.stub_out_jquery();
 
 add_dependencies({
     Handlebars: 'handlebars',
+    colorspace: 'js/colorspace',
     hashchange: 'js/hashchange',
     muting: 'js/muting',
     narrow: 'js/narrow',
@@ -88,31 +89,134 @@ function clear_filters() {
 }());
 
 
-(function test_sort_pin_to_top_streams() {
+(function test_sort_streams() {
     clear_filters();
 
+    // pinned streams
     var develSub = {
         name: 'devel',
         stream_id: 1000,
         color: 'blue',
         id: 5,
-        pin_to_top: false,
+        pin_to_top: true,
         subscribed: true,
     };
     stream_list.create_sidebar_row(develSub);
     global.stream_data.add_sub('devel', develSub);
 
-    var socialSub = {
-        name: 'social',
+    var RomeSub = {
+        name: 'Rome',
         stream_id: 2000,
-        color: 'green',
+        color: 'blue',
         id: 6,
         pin_to_top: true,
         subscribed: true,
     };
+    stream_list.create_sidebar_row(RomeSub);
+    global.stream_data.add_sub('Rome', RomeSub);
+
+    var testSub = {
+        name: 'test',
+        stream_id: 3000,
+        color: 'blue',
+        id: 7,
+        pin_to_top: true,
+        subscribed: true,
+    };
+    stream_list.create_sidebar_row(testSub);
+    global.stream_data.add_sub('test', testSub);
+
+    // unpinned streams
+    var announceSub = {
+        name: 'announce',
+        stream_id: 4000,
+        color: 'green',
+        id: 8,
+        pin_to_top: false,
+        subscribed: true,
+    };
+    stream_list.create_sidebar_row(announceSub);
+    global.stream_data.add_sub('announce', announceSub);
+
+    var DenmarkSub = {
+        name: 'Denmark',
+        stream_id: 5000,
+        color: 'green',
+        id: 9,
+        pin_to_top: false,
+        subscribed: true,
+    };
+    stream_list.create_sidebar_row(DenmarkSub);
+    global.stream_data.add_sub('Denmark', DenmarkSub);
+
+    var socialSub = {
+        name: 'social',
+        stream_id: 6000,
+        color: 'green',
+        id: 10,
+        pin_to_top: false,
+        subscribed: true,
+    };
     stream_list.create_sidebar_row(socialSub);
     global.stream_data.add_sub('social', socialSub);
+
     stream_list.build_stream_list();
-    var li = stream_list.stream_sidebar.get_row(socialSub.stream_id).get_li();
-    assert.equal(li.nextAll().find('[ data-name="devel"]').length, 1);
+
+    // verify pinned streams are sorted by lowercase stream name
+    var devel_li = stream_list.stream_sidebar.get_row(develSub.stream_id).get_li();
+    assert.equal(devel_li.next().find('[ data-name="Rome"]').length, 1);
+    var Rome_li = stream_list.stream_sidebar.get_row(RomeSub.stream_id).get_li();
+    assert.equal(Rome_li.next().find('[ data-name="test"]').length, 1);
+
+    // verify unpinned streams are sorted by lowercase stream name
+    var announce_li = stream_list.stream_sidebar.get_row(announceSub.stream_id).get_li();
+    assert.equal(announce_li.next().find('[ data-name="Denmark"]').length, 1);
+    var Denmark_li = stream_list.stream_sidebar.get_row(DenmarkSub.stream_id).get_li();
+    assert.equal(Denmark_li.next().find('[ data-name="social"]').length, 1);
+
+    // verify pinned streams are sorted before unpinned streams
+    // i.e. the last pinned stream (testSub) is before the first unpinned stream (announceSub)
+    var test_li = stream_list.stream_sidebar.get_row(testSub.stream_id).get_li();
+    assert.equal(test_li.nextAll().find('[ data-name="announce"]').length, 1);
+
+    // add another 40 dummy unpinned streams since sort_recent is set to true only when
+    // there are more than 40 subscribed streams
+    for (var i = 1; i <= 40; i += 1) {
+        var dummyName = 'dummy' + i;
+        var dummySub = {
+            name: dummyName,
+            stream_id: 7000 + i,
+            color: 'green',
+            id: 11 + i,
+            pin_to_top: false,
+            subscribed: true,
+        };
+        stream_list.create_sidebar_row(dummySub);
+        global.stream_data.add_sub(dummyName, dummySub);
+    }
+
+    stream_data.populate_stream_topics_for_tests(
+        // testSub is pinned, DenmarkSub and socialSub are unpinned
+        _.object([testSub.name, socialSub.name, DenmarkSub.name], [testSub, socialSub, DenmarkSub])
+    );
+
+    stream_list.build_stream_list();
+
+    // verify pinned streams are still sorted by lowercase name
+    // i.e. not affected by sort_recent set to true
+    assert.equal(devel_li.next().find('[ data-name="Rome"]').length, 1);
+    assert.equal(Rome_li.next().find('[ data-name="test"]').length, 1);
+
+    // verify DenmarkSub and socialSub are sorted at the top of unpinned streams
+    // because they are active
+    assert.equal(Denmark_li.next().find('[ data-name="social"]').length, 1);
+    var social_li = stream_list.stream_sidebar.get_row(socialSub.stream_id).get_li();
+    assert.equal(social_li.next().find('[ data-name="announce"]').length, 1);
+
+    // verify inactive unpinned streams are still sorted by lowercase stream name
+    assert.equal(announce_li.next().find('[ data-name="dummy1"]').length, 1);
+
+    // verify pinned streams are still sorted before unpinned streams
+    // i.e. the last pinned stream (testSub) is before the first unpinned stream (socialSub)
+    assert.equal(test_li.nextAll().find('[ data-name="social"]').length, 1);
 }());

static/js/stream_list.js

@@ -137,6 +137,8 @@ exports.build_stream_list = function () {
         }
     });
 
+    pinned_streams.sort(util.strcmp);
+
     unpinned_streams.sort(function (a, b) {
         if (sort_recent) {
             if (stream_data.is_active(b) && ! stream_data.is_active(a)) {