1 files changed, 9 insertions, 0 deletions
diff --git a/test/ruby/test_io_m17n.rb b/test/ruby/test_io_m17n.rb
index fbf386548..0a3c403c7 100644
--- a/test/ruby/test_io_m17n.rb
+++ b/test/ruby/test_io_m17n.rb
@@ -121,6 +121,15 @@ EOT
     }
   end
 
+  def test_open_w_enc_enc_perm
+    with_tmpdir {
+      open("tmp", "w:euc-jp:utf-8", 0600) {|f|
+        assert_equal(Encoding::EUC_JP, f.external_encoding)
+        assert_equal(Encoding::UTF_8, f.internal_encoding)
+      }
+    }
+  end
+
   def test_stdin
     assert_equal(Encoding.default_external, STDIN.external_encoding)
     assert_equal(nil, STDIN.internal_encoding)