Expose using_license_seat in users API for admins

ee/changelogs/unreleased/al-36750-expose-using-license-for-admin-users-api.yml

+---
+title: Expose using_license_seat in users API for admins
+merge_request: 43057
+author:
+type: added

ee/lib/ee/api/entities/user_with_admin.rb

+# frozen_string_literal: true
+
+module EE
+  module API
+    module Entities
+      module UserWithAdmin
+        extend ActiveSupport::Concern
+
+        prepended do
+          expose :using_license_seat?, as: :using_license_seat
+        end
+      end
+    end
+  end
+end

ee/spec/lib/ee/api/entities/user_with_admin_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe ::EE::API::Entities::UserWithAdmin do
+  subject { entity.as_json }
+
+  let_it_be(:user) { create(:user) }
+  let(:entity) { ::API::Entities::UserWithAdmin.new(user) }
+
+  context 'using_license_seat' do
+    context 'when user is using seat' do
+      it 'returns true' do
+        expect(subject[:using_license_seat]).to be true
+      end
+    end
+
+    context 'when user is not using seat' do
+      it 'returns false' do
+        allow(user).to receive(:using_license_seat?).and_return(false)
+
+        expect(subject[:using_license_seat]).to be false
+      end
+    end
+  end
+end

lib/api/entities/user_with_admin.rb

@@ -8,3 +8,5 @@ module API
     end
   end
 end
+
+API::Entities::UserWithAdmin.prepend_if_ee('EE::API::Entities::UserWithAdmin')