1 files changed, 5 insertions, 3 deletions
diff --git a/test/ruby/test_exception.rb b/test/ruby/test_exception.rb
index a3b392ae00..f8ddd9d3fa 100644
--- a/test/ruby/test_exception.rb
+++ b/test/ruby/test_exception.rb
@@ -429,9 +429,11 @@ end.join
     bug3237 = '[ruby-core:29948]'
     str = "\u2600"
     id = :"\u2604"
-    msg = "undefined method `#{id}' for #{str.inspect}:String"
-    assert_raise_with_message(NoMethodError, msg, bug3237) do
-      str.__send__(id)
+    EnvUtil.with_default_external(Encoding::UTF_8) do
+      msg = "undefined method `#{id}' for #{str.inspect}:String"
+      assert_raise_with_message(NoMethodError, msg, bug3237) do
+        str.__send__(id)
+      end
     end
   end