diff --git a/actionmailer/test/base_test.rb b/actionmailer/test/base_test.rb
index 3bca69890d..91049e33f9 100644
--- a/actionmailer/test/base_test.rb
+++ b/actionmailer/test/base_test.rb
@@ -829,7 +829,7 @@ class BaseTest < ActiveSupport::TestCase
     assert_equal "special indeed!", mail["X-Special-Header"].to_s
   end
 
-  protected
+  private
 
     # Execute the block setting the given values and restoring old values after
     # the block is executed.
diff --git a/actionmailer/test/i18n_with_controller_test.rb b/actionmailer/test/i18n_with_controller_test.rb
index 039685ffe5..a87a9c9861 100644
--- a/actionmailer/test/i18n_with_controller_test.rb
+++ b/actionmailer/test/i18n_with_controller_test.rb
@@ -66,7 +66,7 @@ class ActionMailerI18nWithControllerTest < ActionDispatch::IntegrationTest
     end
   end
 
-  protected
+  private
 
     def with_translation(locale, data)
       I18n.backend.store_translations(locale, data)
diff --git a/actionmailer/test/mail_helper_test.rb b/actionmailer/test/mail_helper_test.rb
index 972629e477..a2e04b5f48 100644
--- a/actionmailer/test/mail_helper_test.rb
+++ b/actionmailer/test/mail_helper_test.rb
@@ -65,7 +65,7 @@ The second
     end
   end
 
-  protected
+  private
 
     def mail_with_defaults(&block)
       mail(to: "test@localhost", from: "tester@example.com",