Add csv export button do domain list in registrar area

#248

spec/presenters/domain_presenter_spec.rb

@@ -119,6 +119,7 @@ RSpec.describe DomainPresenter do
     name
     registrant_name
     registrant_id
+    registrant_code
   )
 
   domain_delegatable_attributes.each do |attribute_name|

spec/presenters/registrar/domain_list_csv_presenter_spec.rb

@@ -0,0 +1,45 @@
+require 'rails_helper'
+
+RSpec.describe Registrar::DomainListCSVPresenter do
+  let(:domain) { instance_spy(DomainPresenter) }
+  let(:csv) { CSV.parse(described_class.new(domains: [domain], view: view).to_s, converters: :all) }
+
+  describe 'header' do
+    subject(:header) { csv.first }
+
+    it 'is present' do
+      columns = []
+      columns[0] = 'Domain'
+      columns[1] = 'Registrant name'
+      columns[2] = 'Registrant code'
+      columns[3] = 'Date of expiry'
+      columns
+
+      expect(header).to eq(columns)
+    end
+  end
+
+  describe 'row' do
+    subject(:row) { csv.second }
+
+    it 'has domain name' do
+      expect(domain).to receive(:name).and_return('test name')
+      expect(row[0]).to eq('test name')
+    end
+
+    it 'has registrant name' do
+      expect(domain).to receive(:registrant_name).and_return('test registrant name')
+      expect(row[1]).to eq('test registrant name')
+    end
+
+    it 'has registrant code' do
+      expect(domain).to receive(:registrant_code).and_return('test registrant code')
+      expect(row[2]).to eq('test registrant code')
+    end
+
+    it 'has expire date' do
+      expect(domain).to receive(:expire_date).and_return('expire date')
+      expect(row[3]).to eq('expire date')
+    end
+  end
+end