stream_list: Extract initialize_stream_cursor.

This does not create an event handler and thus did not belong in
set_event_handlers.

web/src/stream_list.js

@@ -683,6 +683,24 @@ function actually_update_streams_for_search() {
 
 const update_streams_for_search = _.throttle(actually_update_streams_for_search, 50);
 
+// Exported for tests only.
+export function initialize_stream_cursor() {
+    stream_cursor = new ListCursor({
+        list: {
+            scroll_container_sel: "#left_sidebar_scroll_container",
+            find_li(opts) {
+                const stream_id = opts.key;
+                const li = get_stream_li(stream_id);
+                return li;
+            },
+            first_key: stream_list_sort.first_stream_id,
+            prev_key: stream_list_sort.prev_stream_id,
+            next_key: stream_list_sort.next_stream_id,
+        },
+        highlight_class: "highlighted_stream",
+    });
+}
+
 export function initialize() {
     create_initial_sidebar_rows();
 
@@ -690,6 +708,7 @@ export function initialize() {
     // when new messages come in, but it's fairly quick.
     build_stream_list();
     update_subscribe_to_more_streams_link();
+    initialize_stream_cursor();
     set_event_handlers();
 }
 
@@ -745,21 +764,6 @@ export function set_event_handlers() {
         toggle_pm_header_icon();
     });
 
-    stream_cursor = new ListCursor({
-        list: {
-            scroll_container_sel: "#left_sidebar_scroll_container",
-            find_li(opts) {
-                const stream_id = opts.key;
-                const li = get_stream_li(stream_id);
-                return li;
-            },
-            first_key: stream_list_sort.first_stream_id,
-            prev_key: stream_list_sort.prev_stream_id,
-            next_key: stream_list_sort.next_stream_id,
-        },
-        highlight_class: "highlighted_stream",
-    });
-
     const $search_input = $(".stream-list-filter").expectOne();
 
     keydown_util.handle({

web/tests/stream_list.test.js

@@ -21,9 +21,6 @@ mock_esm("../src/narrow_state", {
     active: () => false,
 });
 const topic_list = mock_esm("../src/topic_list");
-mock_esm("../src/keydown_util", {
-    handle: noop,
-});
 const scroll_util = mock_esm("../src/scroll_util", {
     scroll_element_into_container() {},
     get_scroll_element: ($element) => $element,
@@ -378,7 +375,7 @@ test_ui("zoom_in_and_zoom_out", ({mock_template}) => {
     $("#stream-filters-container")[0] = {
         dataset: {},
     };
-    stream_list.set_event_handlers();
+    stream_list.initialize_stream_cursor();
 
     mock_template("filter_topics", false, () => "filter-topics-stub");
     let filter_topics_appended = false;
@@ -430,8 +427,6 @@ test_ui("narrowing", ({mock_template}) => {
 
     assert.ok(!$("<devel-sidebar-row-stub>").hasClass("active-filter"));
 
-    stream_list.set_event_handlers();
-
     let filter;
 
     filter = new Filter([{operator: "stream", operand: "devel"}]);