Prevent Users tab from disappearing (#4401)

app/lib/ability.rb

@@ -53,7 +53,9 @@ def administrator_abilities(user, resource)
         cannot [:manage_accounts, :manage_billing], Facility.cross_facility
       end
       unless user.account_manager?
-        cannot :manage, User unless resource.is_a?(Facility)
+        # TODO: Refactor
+        # We think this is here to keep the Users tab visible. See LinkCollection#admin_users.
+        cannot :manage, User unless resource.is_a?(Facility) || resource.is_a?(Projects::Project)
         if SettingsHelper.feature_off?(:create_users)
           cannot([:edit, :update], User)
         end

spec/system/admin/projects_show_spec.rb

@@ -156,4 +156,19 @@
       end
     end
   end
+
+  context "global admin tabs" do
+    # https://pm.tablexi.com/issues/162319
+    let(:admin) { create(:user, :administrator) }
+
+    before do
+      login_as admin
+
+      visit facility_project_path(facility, active_project)
+    end
+
+    it "has a link to Users tab" do
+      expect(page).to have_link("Users", href: facility_users_path(facility))
+    end
+  end
 end