node tests: Directly test user_group_pill helpers.

We also sort user_ids to be deterministic.

frontend_tests/node_tests/user_group_pill.js

@@ -11,14 +11,14 @@ const user_group_pill = zrequire("user_group_pill");
 const admins = {
     name: "Admins",
     description: "foo",
-    id: 1,
+    id: 101,
     members: [10, 20],
 };
 const testers = {
     name: "Testers",
     description: "bar",
-    id: 2,
-    members: [20, 30, 40],
+    id: 102,
+    members: [20, 50, 30, 40],
 };
 
 const admins_pill = {
@@ -54,3 +54,19 @@ run_test("create_item", () => {
 run_test("get_stream_id", () => {
     assert.equal(user_group_pill.get_group_name_from_item(admins_pill), admins.name);
 });
+
+run_test("get_user_ids", () => {
+    const items = [admins_pill, testers_pill];
+    const widget = {items: () => items};
+
+    const user_ids = user_group_pill.get_user_ids(widget);
+    assert.deepEqual(user_ids, [10, 20, 30, 40, 50]);
+});
+
+run_test("get_group_ids", () => {
+    const items = [admins_pill, testers_pill];
+    const widget = {items: () => items};
+
+    const group_ids = user_group_pill.get_group_ids(widget);
+    assert.deepEqual(group_ids, [101, 102]);
+});

static/js/user_group_pill.js

@@ -44,6 +44,7 @@ export function get_user_ids(pill_widget) {
     const items = pill_widget.items();
     let user_ids = get_user_ids_from_user_groups(items);
     user_ids = Array.from(new Set(user_ids));
+    user_ids.sort((a, b) => a - b);
 
     user_ids = user_ids.filter(Boolean);
     return user_ids;