1 files changed, 10 insertions, 0 deletions
diff --git a/actionmailer/test/old_base/tmail_compat_test.rb b/actionmailer/test/old_base/tmail_compat_test.rb
index 7c1d9a07c1..255205de84 100644
--- a/actionmailer/test/old_base/tmail_compat_test.rb
+++ b/actionmailer/test/old_base/tmail_compat_test.rb
@@ -21,5 +21,15 @@ class TmailCompatTest < ActiveSupport::TestCase
     end
     assert_equal mail.content_transfer_encoding, "base64"
   end
+
+  def test_transfer_encoding_setter_raises_deprecation_warning
+    mail = Mail.new
+    assert_deprecated do
+      assert_nothing_raised do
+        mail.transfer_encoding = "base64"
+      end
+    end
+    assert_equal mail.content_transfer_encoding, "base64"
+  end
   
 end