add zone label

app/models/zone.rb

@@ -10,5 +10,10 @@
 #
 class Zone < ApplicationRecord
   validates :acronym, presence: true, uniqueness: true
+  has_many :labels, -> { order(designated_on: :desc) }, class_name: 'ZoneLabel', inverse_of: :zone
   has_many :procedures, -> { order(published_at: :desc) }, inverse_of: :zone
+
+  def label
+    labels.first.name
+  end
 end

app/models/zone_label.rb

@@ -0,0 +1,14 @@
+# == Schema Information
+#
+# Table name: zone_labels
+#
+#  id            :bigint           not null, primary key
+#  designated_on :date             not null
+#  name          :string           not null
+#  created_at    :datetime         not null
+#  updated_at    :datetime         not null
+#  zone_id       :bigint           not null
+#
+class ZoneLabel < ApplicationRecord
+  belongs_to :zone
+end

spec/factories/zone.rb

@@ -1,6 +1,14 @@
 FactoryBot.define do
   factory :zone do
     sequence(:acronym) { |n| "MA#{n}" }
-    sequence(:label) { |n| "Ministère de l'Education Populaire #{n}" }
+    transient do
+      labels { [{ designated_on: '1981-05-08', name: "Ministère de l'Education Populaire" }] }
+    end
+
+    after(:create) do |zone, evaluator|
+      evaluator.labels.each do |label|
+        zone.labels.create(designated_on: label[:designated_on], name: label[:name])
+      end
+    end
   end
 end

spec/models/zone_spec.rb

@@ -0,0 +1,32 @@
+describe Zone do
+  let(:now) { Time.zone.parse("2022-08-11") }
+  before do
+    Timecop.freeze(now)
+  end
+
+  after do
+    Timecop.return
+  end
+
+  describe '#label' do
+    let(:start_previous_government) { Date.parse('2020-07-06') }
+    let(:start_last_government) { Date.parse('2022-05-20') }
+    let(:zone) do
+      create(:zone, labels: [
+        {
+          designated_on: start_previous_government,
+          name: "Ministère de l'Économie, des Finances et de la Relance"
+        },
+        {
+          designated_on: start_last_government,
+          name: "Ministère de l'Économie, des Finances et de la Souveraineté industrielle et numérique"
+        }
+      ])
+    end
+
+    it 'returns label for the current millesime' do
+      expect(zone.label).to eq "Ministère de l'Économie, des Finances et de la Souveraineté industrielle et numérique"
+    end
+  end
+end
+