1 files changed, 24 insertions, 20 deletions
diff --git a/actionmailer/lib/action_mailer/test_case.rb b/actionmailer/lib/action_mailer/test_case.rb
index 65e7347ae4..ee5a864847 100644
--- a/actionmailer/lib/action_mailer/test_case.rb
+++ b/actionmailer/lib/action_mailer/test_case.rb
@@ -1,11 +1,13 @@
-require 'active_support/test_case'
-require 'rails-dom-testing'
+# frozen_string_literal: true
+
+require "active_support/test_case"
+require "rails-dom-testing"
 
 module ActionMailer
   class NonInferrableMailerError < ::StandardError
     def initialize(name)
-      super "Unable to determine the mailer to test from #{name}. " +
-        "You'll need to specify it using tests YourMailer in your " +
+      super "Unable to determine the mailer to test from #{name}. " \
+        "You'll need to specify it using tests YourMailer in your " \
         "test case definition"
     end
   end
@@ -15,15 +17,17 @@ module ActionMailer
       extend ActiveSupport::Concern
 
       included do
+        setup :clear_test_deliveries
         teardown :clear_test_deliveries
       end
 
       private
-      def clear_test_deliveries
-        if ActionMailer::Base.delivery_method == :test
-          ActionMailer::Base.deliveries.clear
+
+        def clear_test_deliveries
+          if ActionMailer::Base.delivery_method == :test
+            ActionMailer::Base.deliveries.clear
+          end
         end
-      end
     end
 
     module Behavior
@@ -39,6 +43,7 @@ module ActionMailer
         setup :initialize_test_deliveries
         setup :set_expected_mail
         teardown :restore_test_deliveries
+        ActiveSupport.run_load_hooks(:action_mailer_test_case, self)
       end
 
       module ClassMethods
@@ -54,7 +59,7 @@ module ActionMailer
         end
 
         def mailer_class
-          if mailer = self._mailer_class
+          if mailer = _mailer_class
             mailer
           else
             tests determine_default_mailer(name)
@@ -70,36 +75,36 @@ module ActionMailer
         end
       end
 
-      protected
+      private
 
-        def initialize_test_deliveries # :nodoc:
+        def initialize_test_deliveries
           set_delivery_method :test
           @old_perform_deliveries = ActionMailer::Base.perform_deliveries
           ActionMailer::Base.perform_deliveries = true
+          ActionMailer::Base.deliveries.clear
         end
 
-        def restore_test_deliveries # :nodoc:
+        def restore_test_deliveries
           restore_delivery_method
           ActionMailer::Base.perform_deliveries = @old_perform_deliveries
         end
 
-        def set_delivery_method(method) # :nodoc:
+        def set_delivery_method(method)
           @old_delivery_method = ActionMailer::Base.delivery_method
           ActionMailer::Base.delivery_method = method
         end
 
-        def restore_delivery_method # :nodoc:
+        def restore_delivery_method
+          ActionMailer::Base.deliveries.clear
           ActionMailer::Base.delivery_method = @old_delivery_method
         end
 
-        def set_expected_mail # :nodoc:
+        def set_expected_mail
           @expected = Mail.new
           @expected.content_type ["text", "plain", { "charset" => charset }]
-          @expected.mime_version = '1.0'
+          @expected.mime_version = "1.0"
         end
 
-      private
-
         def charset
           "UTF-8"
         end
@@ -109,11 +114,10 @@ module ActionMailer
         end
 
         def read_fixture(action)
-          IO.readlines(File.join(Rails.root, 'test', 'fixtures', self.class.mailer_class.name.underscore, action))
+          IO.readlines(File.join(Rails.root, "test", "fixtures", self.class.mailer_class.name.underscore, action))
         end
     end
 
     include Behavior
-    include ClearTestDeliveries
   end
 end