bot settings: Clear typeahead when renaming a bot

Fixes #7534
When bot is renamed, the old name persists in mention typehead.
This commit clears the typeahead, whenever bot details are modified.

frontend_tests/node_tests/typeahead_helper.js

@@ -399,6 +399,32 @@ _.each(matches, function (person) {
     assert(rendered);
 }());
 
+(function test_clear_rendered_persons() {
+    var rendered = false;
+    global.templates.render = function (template_name, args) {
+        assert.equal(template_name, 'typeahead_list_item');
+        assert.equal(args.primary, matches[5].full_name);
+        assert.equal(args.secondary, matches[5].email);
+        rendered = true;
+        return 'typeahead-item-stub';
+    };
+    assert.equal(th.render_person(matches[5]), 'typeahead-item-stub');
+    assert(rendered);
+
+    // Bot once rendered won't be rendered again until clear_rendered_person
+    // function is called. clear_rendered_person is used to clear rendered
+    // data once bot name is modified.
+    rendered = false;
+    assert.equal(th.render_person(matches[5]), 'typeahead-item-stub');
+    assert.equal(rendered, false);
+
+    // Here rendered will be true as it is being rendered again.
+    th.clear_rendered_persons();
+    assert.equal(th.render_person(matches[5]), 'typeahead-item-stub');
+    assert(rendered);
+
+}());
+
 (function test_render_stream() {
     // Test render_stream with short description
     var rendered = false;

static/js/settings_bots.js

@@ -306,6 +306,7 @@ exports.set_up = function () {
                         edit_button.show();
                         show_row_again();
                         avatar_widget.clear();
+                        typeahead_helper.clear_rendered_persons();
 
                         bot_info.find('.name').text(full_name);
                         if (data.avatar_url) {

static/js/typeahead_helper.js

@@ -94,6 +94,10 @@ exports.render_person = function (person) {
     return html;
 };
 
+exports.clear_rendered_persons = function () {
+    rendered.persons.clear();
+};
+
 exports.render_user_group = function (user_group) {
     var html = rendered.user_groups.get(user_group.id);
     if (html === undefined) {