[#1421] Extract values for both drop down lists

app/models/champs/linked_drop_down_list_champ.rb

@@ -1,3 +1,32 @@
 class Champs::LinkedDropDownListChamp < Champ
+  attr_reader :master_value, :slave_value
   delegate :master_options, :slave_options, to: :type_de_champ
+
+  after_initialize :unpack_value
+
+  def unpack_value
+    if value.present?
+      master, slave = JSON.parse(value)
+    else
+      master = slave = ''
+    end
+    @master_value ||= master
+    @slave_value ||= slave
+  end
+
+  def master_value=(value)
+    @master_value = value
+    pack_value
+  end
+
+  def slave_value=(value)
+    @slave_value = value
+    pack_value
+  end
+
+  private
+
+  def pack_value
+    self.value = JSON.generate([ master_value, slave_value ])
+  end
 end

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