1 files changed, 9 insertions, 0 deletions
diff --git a/test/-ext-/string/test_enc_str_buf_cat.rb b/test/-ext-/string/test_enc_str_buf_cat.rb
index 72f903903c..b9a63ec2de 100644
--- a/test/-ext-/string/test_enc_str_buf_cat.rb
+++ b/test/-ext-/string/test_enc_str_buf_cat.rb
@@ -13,4 +13,13 @@ class Test_StringEncStrBufCat < Test::Unit::TestCase
     assert_equal(:unknown, Bug::String.new(cr_unknown_str).coderange, "an assertion for following tests")
     assert_equal(:valid, Bug::String.new(a8_str).enc_str_buf_cat(cr_unknown_str).coderange, Bug6509)
   end
+
+  def test_str_conv_enc
+    str = Bug::String.new("aaa".encode("US-ASCII"))
+    assert_same(str, str.str_conv_enc_opts("UTF-8", "US-ASCII", 0, nil))
+
+    str = Bug::String.new("aaa".encode("UTF-16LE").force_encoding("UTF-8"))
+    assert_predicate(str, :ascii_only?) # cache coderange
+    assert_equal("aaa", str.str_conv_enc_opts("UTF-16LE", "UTF-8", 0, nil))
+  end
 end