4 files changed, 24 insertions, 2 deletions
diff --git a/actionmailer/lib/action_mailer.rb b/actionmailer/lib/action_mailer.rb
index 291a8c1e34..312dd1997c 100644
--- a/actionmailer/lib/action_mailer.rb
+++ b/actionmailer/lib/action_mailer.rb
@@ -49,3 +49,10 @@ module ActionMailer
   autoload :MessageDelivery
   autoload :DeliveryJob
 end
+
+autoload :Mime, 'action_dispatch/http/mime_type'
+
+ActiveSupport.on_load(:action_view) do
+  ActionView::Base.default_formats ||= Mime::SET.symbols
+  ActionView::Template::Types.delegate_to Mime
+end
diff --git a/actionmailer/test/base_test.rb b/actionmailer/test/base_test.rb
index 6b2e6a531c..50f2c71737 100644
--- a/actionmailer/test/base_test.rb
+++ b/actionmailer/test/base_test.rb
@@ -449,6 +449,13 @@ class BaseTest < ActiveSupport::TestCase
     assert_equal("Format with any!", email.parts[1].body.encoded)
   end
 
+  test 'explicit without specifying format with format.any' do
+    error = assert_raises(ArgumentError) do
+      BaseMailer.explicit_without_specifying_format_with_any.parts
+    end
+    assert_equal "You have to supply at least one format", error.message
+  end
+
   test "explicit multipart with format(Hash)" do
     email = BaseMailer.explicit_multipart_with_options(true)
     email.ready_to_send!
diff --git a/actionmailer/test/delivery_methods_test.rb b/actionmailer/test/delivery_methods_test.rb
index ceaa4ca83e..d17e774092 100644
--- a/actionmailer/test/delivery_methods_test.rb
+++ b/actionmailer/test/delivery_methods_test.rb
@@ -165,16 +165,18 @@ class MailDeliveryTest < ActiveSupport::TestCase
 
   test "non registered delivery methods raises errors" do
     DeliveryMailer.delivery_method = :unknown
-    assert_raise RuntimeError do
+    error = assert_raise RuntimeError do
       DeliveryMailer.welcome.deliver_now
     end
+    assert_equal "Invalid delivery method :unknown", error.message
   end
 
   test "undefined delivery methods raises errors" do
     DeliveryMailer.delivery_method = nil
-    assert_raise RuntimeError do
+    error = assert_raise RuntimeError do
       DeliveryMailer.welcome.deliver_now
     end
+    assert_equal "Delivery method cannot be nil", error.message
   end
 
   test "does not perform deliveries if requested" do
diff --git a/actionmailer/test/mailers/base_mailer.rb b/actionmailer/test/mailers/base_mailer.rb
index bd991e209e..8c2225ce60 100644
--- a/actionmailer/test/mailers/base_mailer.rb
+++ b/actionmailer/test/mailers/base_mailer.rb
@@ -80,6 +80,12 @@ class BaseMailer < ActionMailer::Base
     end
   end
 
+  def explicit_without_specifying_format_with_any(hash = {})
+    mail(hash) do |format|
+      format.any
+    end
+  end
+
   def explicit_multipart_with_options(include_html = false)
     mail do |format|
       format.text(content_transfer_encoding: "base64"){ render "welcome" }