Refactor IP registrar restriction

#600

spec/features/registrar/sessions/new_spec.rb

@@ -0,0 +1,42 @@
+require 'rails_helper'
+
+RSpec.feature 'Registrar area ip restriction', settings: false do
+  context 'when enabled' do
+    background do
+      Setting.registrar_ip_whitelist_enabled = true
+    end
+
+    context 'when ip is allowed' do
+      given!(:white_ip) { create(:white_ip,
+                                 ipv4: '127.0.0.1',
+                                 interfaces: [WhiteIp::REGISTRAR]) }
+
+      it 'does not show error message' do
+        visit registrar_login_path
+        expect(page).to_not have_text(error_message)
+      end
+    end
+
+    context 'when ip is not allowed' do
+      it 'shows error message' do
+        visit registrar_login_path
+        expect(page).to have_text(error_message)
+      end
+    end
+  end
+
+  context 'when disabled' do
+    background do
+      Setting.registrar_ip_whitelist_enabled = false
+    end
+
+    it 'does not show error message' do
+      visit registrar_login_path
+      expect(page).to_not have_text(error_message)
+    end
+  end
+
+  def error_message
+    t('registrar.authorization.ip_not_allowed', ip: '127.0.0.1')
+  end
+end