Add controller tests

Co-authored-by: viehlieb <pf@pragma-shift.net>
Co-authored-by: Tobias Kneuker <tk@pragma-shift.net>

seperate expects

refactor login user calls

add more articles to test sorting with

fix: fix test for rails upgrade

spec/factories/order_article.rb

@@ -0,0 +1,8 @@
+require 'factory_bot'
+
+FactoryBot.define do
+  factory :order_article do
+    order { create :order }
+    article { create :article }
+  end
+end