Have "n" key skip muted streams.

frontend_tests/node_tests/topic_generator.js

@@ -158,10 +158,15 @@ function is_odd(i) { return i % 2 === 1; }
     var curr_topic = 'whatever';
 
     global.stream_sort.get_streams = function () {
-        return ['announce', 'devel', 'test here'];
+        return ['announce', 'muted', 'devel', 'test here'];
     };
 
     global.stream_data.get_recent_topics = function (stream) {
+        if (stream === 'muted') {
+            return [
+                {subject: 'red herring'},
+            ];
+        }
         if (stream === 'devel') {
             return [
                 {subject: 'muted'},
@@ -180,6 +185,10 @@ function is_odd(i) { return i % 2 === 1; }
         return 999;
     };
 
+    global.stream_data.name_in_home_view = function (stream_name) {
+        return (stream_name !== 'muted');
+    };
+
     global.unread.topic_has_any_unread = function (stream_id) {
         return (stream_id === devel_stream_id);
     };

static/js/topic_generator.js

@@ -158,6 +158,10 @@ exports.next_topic = function (streams, get_topics, has_unread_messages, curr_st
 exports.get_next_topic = function (curr_stream, curr_topic) {
     var my_streams = stream_sort.get_streams();
 
+    my_streams = _.filter(my_streams, function (stream_name) {
+        return stream_data.name_in_home_view(stream_name);
+    });
+
     function get_unmuted_topics(stream_name) {
         var topic_objs = stream_data.get_recent_topics(stream_name) || [];
         var topics = _.map(topic_objs, function (obj) { return obj.subject; });