Fix inheriting mailer templates from Devise::Mailer

Previously inheriting from Devise::Mailer would not render default views
from devise when the inheriting mailer didn't have the view. Now it'll
correctly pick the default one from Devise::Mailer.

CHANGELOG.rdoc

@@ -1,3 +1,8 @@
+== master
+
+* bug fix
+  * Fix inheriting mailer templates from `Devise::Mailer`
+
 == 2.2.3
 
 * bug fix

lib/devise/mailers/helpers.rb

@@ -64,7 +64,7 @@ module Devise
       end
 
       def template_paths
-        template_path = [self.class.mailer_name]
+        template_path = _prefixes.dup
         template_path.unshift "#{@devise_mapping.scoped_path}/mailer" if self.class.scoped_views?
         template_path
       end

test/mailers/confirmation_instructions_test.rb

@@ -46,6 +46,11 @@ class ConfirmationInstructionsTest < ActionMailer::TestCase
     assert_equal ['custom@example.com'], mail.from
   end
 
+  test 'custom mailer renders parent mailer template' do
+    Devise.mailer = 'Users::Mailer'
+    assert_not_blank mail.body.encoded
+  end
+
   test 'setup reply to as copy from sender' do
     assert_equal ['test@example.com'], mail.reply_to
   end
@@ -56,7 +61,6 @@ class ConfirmationInstructionsTest < ActionMailer::TestCase
     assert_equal ['custom_reply_to@example.com'], mail.reply_to
   end
 
-
   test 'setup subject from I18n' do
     store_translations :en, :devise => { :mailer => { :confirmation_instructions => { :subject => 'Account Confirmation' } } } do
       assert_equal 'Account Confirmation', mail.subject

test/mailers/reset_password_instructions_test.rb

@@ -1,7 +1,6 @@
 require 'test_helper'
 
 class ResetPasswordInstructionsTest < ActionMailer::TestCase
-
   def setup
     setup_mailer
     Devise.mailer = 'Devise::Mailer'
@@ -49,6 +48,11 @@ class ResetPasswordInstructionsTest < ActionMailer::TestCase
     assert_equal ['custom@example.com'], mail.from
   end
 
+  test 'custom mailer renders parent mailer template' do
+    Devise.mailer = 'Users::Mailer'
+    assert_not_blank mail.body.encoded
+  end
+
   test 'setup reply to as copy from sender' do
     assert_equal ['test@example.com'], mail.reply_to
   end

test/mailers/unlock_instructions_test.rb

@@ -49,6 +49,11 @@ class UnlockInstructionsTest < ActionMailer::TestCase
     assert_equal ['custom@example.com'], mail.from
   end
 
+  test 'custom mailer renders parent mailer template' do
+    Devise.mailer = 'Users::Mailer'
+    assert_not_blank mail.body.encoded
+  end
+
   test 'setup reply to as copy from sender' do
     assert_equal ['test@example.com'], mail.reply_to
   end