article_spec: add deleted test

spec/models/article_spec.rb

@@ -9,6 +9,11 @@ describe Article do
     expect(article2).to be_invalid
   end
 
+  it 'can be deleted' do
+    article.mark_as_deleted()
+    expect(article.deleted?).to be true
+  end
+
   it 'computes the gross price correctly' do
     article.deposit = 0
     article.tax = 12

spec/models/order_article_spec.rb

@@ -4,6 +4,10 @@ describe OrderArticle do
   let(:order) { create :order, article_count: 1 }
   let(:oa) { order.order_articles.first }
 
+  it 'foo' do
+    oa.update_article_and_price!()
+  end
+
   it 'is not ordered by default' do
     expect(OrderArticle.ordered.count).to eq 0
   end