Add registrar vat rate

#623

test/models/registrar/vat_test.rb

@@ -0,0 +1,73 @@
+require 'test_helper'
+
+class RegistrarVATTest < ActiveSupport::TestCase
+  def setup
+    @registrar = registrars(:bestnames)
+  end
+
+  def test_optional_vat_no
+    @registrar.vat_no = ''
+    assert @registrar.valid?
+
+    @registrar.vat_no = 'any'
+    assert @registrar.valid?
+  end
+
+  def test_requires_vat_rate_when_registrar_is_foreign_vat_payer_and_vat_no_is_absent
+    @registrar.vat_no = ''
+
+    Registry.instance.stub(:legal_address_country, Country.new('GB')) do
+      @registrar.vat_rate = ''
+      assert @registrar.invalid?
+      assert @registrar.errors.added?(:vat_rate, :blank)
+
+      @registrar.vat_rate = -1
+      assert @registrar.invalid?
+
+      @registrar.vat_rate = 1
+      assert @registrar.valid?
+
+      @registrar.vat_rate = 99.9
+      assert @registrar.valid?
+
+      @registrar.vat_rate = 100
+      assert @registrar.invalid?
+    end
+  end
+
+  def test_vat_is_not_applied_when_registrar_is_local_vat_payer
+    @registrar.vat_rate = 1
+    assert @registrar.invalid?
+
+    @registrar.vat_rate = nil
+    assert @registrar.valid?
+  end
+
+  def test_vat_is_not_applied_when_registrar_is_foreign_vat_payer_and_vat_no_is_present
+    @registrar.vat_no = 'valid'
+
+    Registry.instance.stub(:legal_address_country, Country.new('GB')) do
+      @registrar.vat_rate = 1
+      assert @registrar.invalid?
+
+      @registrar.vat_rate = nil
+      assert @registrar.valid?
+    end
+  end
+
+  def test_serializes_and_deserializes_vat_rate
+    @registrar.vat_rate = '25.5'
+
+    Registry.instance.stub(:legal_address_country, Country.new('GB')) do
+      @registrar.save!
+    end
+
+    @registrar.reload
+    assert_equal 25.5, @registrar.vat_rate
+  end
+
+  def test_treats_empty_vat_rate_as_absent
+    @registrar.vat_rate = ''
+    assert_nil @registrar.vat_rate
+  end
+end