reset `ActionMailer::Base.deliveries` in `ActionDispatch::IntegrationTest`.

Whenever you are sending emails in integration tests using the `:test`
delivery method you need to make sure that
`ActionMailer::Base.deliveries` is reset after every test. This piece of
boilerplate code is present in all my applications that send
emails. Let's have `ActionDispatch::IntegrationTest` reset the
deliveries automatically.

2 files changed, 18 insertions, 1 deletions

diff --git a/actionmailer/lib/action_mailer/railtie.rb b/actionmailer/lib/action_mailer/railtie.rb
index fa707021c7..00e3972196 100644
--- a/actionmailer/lib/action_mailer/railtie.rb
+++ b/actionmailer/lib/action_mailer/railtie.rb
@@ -51,6 +51,8 @@ module ActionMailer
             get '/rails/mailers/*path'   => "rails/mailers#preview"
           end
         end
+
+        ActionDispatch::IntegrationTest.send :include, ActionMailer::TestCase::ClearTestDeliviers
       end
     end
 
diff --git a/actionmailer/lib/action_mailer/test_case.rb b/actionmailer/lib/action_mailer/test_case.rb
index 0aa15e31ba..063d2180f8 100644
--- a/actionmailer/lib/action_mailer/test_case.rb
+++ b/actionmailer/lib/action_mailer/test_case.rb
@@ -11,6 +11,21 @@ module ActionMailer
   end
 
   class TestCase < ActiveSupport::TestCase
+    module ClearTestDeliviers
+      extend ActiveSupport::Concern
+
+      included do
+        teardown :clear_test_deliviers
+      end
+
+      private
+      def clear_test_deliviers
+        if ActionMailer::Base.delivery_method == :test
+          ActionMailer::Base.deliveries.clear
+        end
+      end
+    end
+
     module Behavior
       extend ActiveSupport::Concern
 
@@ -66,7 +81,6 @@ module ActionMailer
         def restore_test_deliveries # :nodoc:
           restore_delivery_method
           ActionMailer::Base.perform_deliveries = @old_perform_deliveries
-          ActionMailer::Base.deliveries.clear
         end
 
         def set_delivery_method(method) # :nodoc:
@@ -100,5 +114,6 @@ module ActionMailer
     end
 
     include Behavior
+    include ClearTestDeliviers
   end
 end