[#1421] Extract values for both drop down lists

spec/models/champs/linked_drop_down_list_champ_spec.rb

@@ -0,0 +1,18 @@
+require 'spec_helper'
+
+describe Champs::LinkedDropDownListChamp do
+  describe '#unpack_value' do
+    let(:champ) { described_class.new(value: '["tata", "tutu"]') }
+
+    it { expect(champ.master_value).to eq('tata') }
+    it { expect(champ.slave_value).to eq('tutu') }
+  end
+
+  describe '#pack_value' do
+    let(:champ) { described_class.new(master_value: 'tata', slave_value: 'tutu') }
+
+    before { champ.save }
+
+    it { expect(champ.value).to eq('["tata","tutu"]') }
+  end
+end