Ensure that Whois record is updated/destroyed when actions performed on Zone objects

test/models/dns/zone_test.rb

@@ -124,6 +124,31 @@ class DNS::ZoneTest < ActiveSupport::TestCase
     assert zone.invalid?
   end
 
+  def test_determines_if_subzone
+    zone = valid_zone
+    zone.update(origin: 'pri.ee')
+    assert zone.subzone?
+  end
+
+  def test_updates_whois_after_update
+    subzone = dns_zones(:subzone)
+    assert_nil Whois::Record.find_by(name: subzone.origin)
+
+    subzone.update(expire: 42)
+
+    whois_record = Whois::Record.find_by(name: subzone.origin)
+    assert whois_record.present?
+  end
+
+  def test_deletes_whois_record_after_destroy
+    subzone = dns_zones(:subzone)
+    subzone.update(expire: 42)
+    assert Whois::Record.find_by(name: subzone.origin).present?
+
+    subzone.destroy
+    assert_nil Whois::Record.find_by(name: subzone.origin)
+  end
+
   private
 
   def valid_zone