FIX: Order items properly in user menu

The recent changes to the user menu changed how we were ordering the
items in it. A small bug was noticed though, as we’re not displaying the
unread assignments at the very top.

This patch fixes the ordering like this:

- Unread individual assignment notifications
- Unread group assignment notifications
- Read individual assignments
- Read group assignments

In each group of items, they are sorted by date, the most recent ones
being at the top.

assets/javascripts/discourse/components/user-menu/assigns-list.js

@@ -1,3 +1,5 @@
+import { set } from "@ember/object";
+import { sort } from "@ember/object/computed";
 import UserMenuNotificationsList from "discourse/components/user-menu/notifications-list";
 import I18n from "I18n";
 import UserMenuAssignsListEmptyState from "./assigns-list-empty-state";
@@ -51,10 +53,20 @@ export default class UserMenuAssignNotificationsList extends UserMenuNotificatio
   }
 
   async fetchItems() {
-    // sorting by `data.message` length to group single user assignments and
+    return new SortedItems(await super.fetchItems()).sortedItems;
-    // group assignments, then by `created_at` to keep chronological order.
+  }
-    return (await super.fetchItems())
+}
-      .sortBy("notification.data.message", "notification.created_at")
+
-      .reverse();
+class SortedItems {
+  itemsSorting = [
+    "notification.read",
+    "notification.data.message:desc",
+    "notification.created_at:desc",
+  ];
+
+  @sort("items", "itemsSorting") sortedItems;
+
+  constructor(items) {
+    set(this, "items", items);
   }
 }

spec/fabricators/notification_fabricator.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+Fabricator(:assignment_notification, from: :notification) do
+  transient :group
+  notification_type Notification.types[:assigned]
+  post_number 1
+  data do |attrs|
+    {
+      message:
+        (
+          if attrs[:group]
+            "discourse_assign.assign_group_notification"
+          else
+            "discourse_assign.assign_notification"
+          end
+        ),
+      display_username: attrs[:group] ? "group" : "user",
+      assignment_id: rand(1..100),
+    }.to_json
+  end
+end

spec/system/page_objects/pages/user_menu.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module PageObjects
+  module Components
+    class UserMenu < PageObjects::Components::Base
+      def click_assignments_tab
+        click_link("user-menu-button-assign-list")
+        has_css?("#quick-access-assign-list")
+        self
+      end
+
+      def has_assignments_in_order?(assignments)
+        expect(all(".notification.assigned .item-description").map(&:text)).to eq(assignments)
+      end
+    end
+  end
+end

spec/system/user_menu_spec.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+RSpec.describe "Assign | User Menu", type: :system, js: true do
+  fab!(:admin) { Fabricate(:admin) }
+
+  let(:user_menu) { PageObjects::Components::UserMenu.new }
+
+  before do
+    SiteSetting.assign_enabled = true
+    sign_in(admin)
+  end
+
+  describe "Assign tab ordering" do
+    let!(:unread_user_assign) { Fabricate(:assignment_notification, user: admin) }
+    let!(:unread_user_assign_2) { Fabricate(:assignment_notification, user: admin) }
+    let!(:read_user_assign) { Fabricate(:assignment_notification, user: admin, read: true) }
+    let!(:read_user_assign_2) { Fabricate(:assignment_notification, user: admin, read: true) }
+    let!(:unread_group_assign) { Fabricate(:assignment_notification, user: admin, group: true) }
+    let!(:read_group_assign) do
+      Fabricate(:assignment_notification, user: admin, read: true, group: true)
+    end
+    let(:expected_order) do
+      [
+        unread_user_assign_2,
+        unread_user_assign,
+        unread_group_assign,
+        read_user_assign_2,
+        read_user_assign,
+        read_group_assign,
+      ].map { _1.topic.fancy_title }
+    end
+
+    it "orders the items properly" do
+      visit "/"
+      user_menu.open
+      user_menu.click_assignments_tab
+      expect(user_menu).to have_assignments_in_order(expected_order)
+    end
+  end
+end