Refactor contact mailer

- Send single email with new email in `to` and old email in `bcc` fields
- Remove `Que::Mailer` (#895)
- Add preview
- DRY templates
- Add tests
- Extract translations
- Remove useless specs

test/integration/epp/contact/update/base_test.rb

@@ -1,8 +1,11 @@
 require 'test_helper'
 
 class EppContactUpdateBaseTest < ActionDispatch::IntegrationTest
+  include ActionMailer::TestHelper
+
   setup do
     @contact = contacts(:john)
+    ActionMailer::Base.deliveries.clear
   end
 
   def test_updates_contact
@@ -45,6 +48,62 @@ class EppContactUpdateBaseTest < ActionDispatch::IntegrationTest
     assert_equal '+123.4', @contact.phone
   end
 
+  def test_notifies_a_contact_when_an_email_is_changed
+    assert_equal 'john-001', @contact.code
+    assert_not_equal 'new@inbox.test', @contact.email
+
+    # https://github.com/internetee/registry/issues/415
+    @contact.update_columns(code: @contact.code.upcase)
+
+    request_xml = <<-XML
+      <?xml version="1.0" encoding="UTF-8" standalone="no"?>
+      <epp xmlns="https://epp.tld.ee/schema/epp-ee-1.0.xsd">
+        <command>
+          <update>
+            <contact:update xmlns:contact="https://epp.tld.ee/schema/contact-ee-1.1.xsd">
+              <contact:id>john-001</contact:id>
+              <contact:chg>
+                <contact:email>new@inbox.test</contact:email>
+              </contact:chg>
+            </contact:update>
+          </update>
+        </command>
+      </epp>
+    XML
+
+    post '/epp/command/update', { frame: request_xml }, 'HTTP_COOKIE' => 'session=api_bestnames'
+
+    assert_emails 1
+  end
+
+  def test_skips_notifying_a_contact_when_an_email_is_not_changed
+    assert_equal 'john-001', @contact.code
+    assert_equal 'john@inbox.test', @contact.email
+
+    # https://github.com/internetee/registry/issues/415
+    @contact.update_columns(code: @contact.code.upcase)
+
+    request_xml = <<-XML
+      <?xml version="1.0" encoding="UTF-8" standalone="no"?>
+      <epp xmlns="https://epp.tld.ee/schema/epp-ee-1.0.xsd">
+        <command>
+          <update>
+            <contact:update xmlns:contact="https://epp.tld.ee/schema/contact-ee-1.1.xsd">
+              <contact:id>john-001</contact:id>
+              <contact:chg>
+                <contact:email>john@inbox.test</contact:email>
+              </contact:chg>
+            </contact:update>
+          </update>
+        </command>
+      </epp>
+    XML
+
+    post '/epp/command/update', { frame: request_xml }, 'HTTP_COOKIE' => 'session=api_bestnames'
+
+    assert_no_emails
+  end
+
   def test_non_existing_contact
     assert_nil Contact.find_by(code: 'non-existing')
 

test/mailers/contact_mailer_test.rb

@@ -0,0 +1,24 @@
+require 'test_helper'
+
+class ContactMailerTest < ActiveSupport::TestCase
+  include ActionMailer::TestHelper
+
+  setup do
+    @contact = contacts(:john)
+    ActionMailer::Base.deliveries.clear
+  end
+
+  def test_delivers_email_changed_email
+    assert_equal 'john-001', @contact.code
+    assert_equal 'john@inbox.test', @contact.email
+
+    email = ContactMailer.email_changed(contact: @contact, old_email: 'john-old@inbox.test')
+              .deliver_now
+
+    assert_emails 1
+    assert_equal %w[john@inbox.test], email.to
+    assert_equal %w[john-old@inbox.test], email.bcc
+    assert_equal 'Teie domeenide kontakt epostiaadress on muutunud' \
+                 ' / Contact e-mail addresses of your domains have changed [john-001]', email.subject
+  end
+end

test/mailers/previews/contact_mailer_preview.rb

@@ -0,0 +1,13 @@
+class ContactMailerPreview < ActionMailer::Preview
+  def email_changed
+    # Replace with `Contact.in_use` once https://github.com/internetee/registry/pull/1146 is merged
+    contact = Contact.where('EXISTS(SELECT 1 FROM domains WHERE domains.registrant_id = contacts.id)
+                             OR
+                             EXISTS(SELECT 1 FROM domain_contacts WHERE domain_contacts.contact_id =
+                             contacts.id)')
+
+    contact = contact.where.not(email: nil, country_code: nil, code: nil).first
+
+    ContactMailer.email_changed(contact: contact, old_email: 'old@inbox.test')
+  end
+end