1 files changed, 20 insertions, 1 deletions
diff --git a/test/ruby/test_encoding.rb b/test/ruby/test_encoding.rb
index 7ccbb31f50..0cd5bf49dc 100644
--- a/test/ruby/test_encoding.rb
+++ b/test/ruby/test_encoding.rb
@@ -154,7 +154,26 @@ class TestEncoding < Test::Unit::TestCase
         r, _obj = Ractor.select(*rs)
         rs.delete(r)
       end
-      assert rs.empty?
+      assert_empty rs
+    end;
+  end
+
+  def test_ractor_set_default_external_string
+    assert_ractor("#{<<~"begin;"}\n#{<<~'end;'}")
+    begin;
+    $-w = nil
+    rs = []
+    7.times do |i|
+      rs << Ractor.new(i) do |i|
+        Encoding.default_external = "us-ascii"
+      end
+    end
+
+    while rs.any?
+      r, _obj = Ractor.select(*rs)
+      rs.delete(r)
+    end
+    assert_empty rs
     end;
   end
 end