add specs

app/controllers/order_invoices_controller_base.rb

@@ -0,0 +1,44 @@
+class OrderInvoicesControllerBase < ApplicationController
+  before_action :authenticate_finance
+
+  def select_sepa_sequence_type
+    @invoice = invoice_class.find(params[:id])
+    return unless params[:sepa_sequence_type]
+
+    @group_order = set_related_group_order(@invoice)
+    @multi_group_order = set_related_group_order(@invoice)
+
+    @invoice.sepa_sequence_type = params[:sepa_sequence_type]
+    save_and_respond(@invoice)
+  end
+
+  def toggle_paid
+    @invoice = invoice_class.find(params[:id])
+    @invoice.paid = !@invoice.paid
+    save_and_respond(@invoice)
+  end
+
+  def toggle_sepa_downloaded
+    @invoice = invoice_class.find(params[:id])
+    @invoice.sepa_downloaded = !@invoice.sepa_downloaded
+    save_and_respond(@invoice)
+  end
+
+  protected
+
+  def save_and_respond(record)
+    if record.save!
+      respond_to { |format| format.js }
+    else
+      respond_to { |format| format.json { render json: record.errors, status: :unprocessable_entity } }
+    end
+  end
+
+  def invoice_class
+    raise NotImplementedError
+  end
+
+  def set_related_group_order(invoice)
+    raise NotImplementedError
+  end
+end