diff --git a/ChangeLog b/ChangeLog
index 338eb1135a..c54ccb18bd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Dec 13 13:41:44 2008  Yuki Sonoda (Yugui)  <yugui@yugui.jp>
+
+	* test/ruby/test_m17n_comb.rb: feature changed in r20626.
+	  follows it.
+
 Sat Dec 13 13:03:20 2008  Tadayoshi Funaba  <tadf@dotrb.org>
 
 	* complex.c: use rb_usascii_str_new2 instead of rb_str_new2.
diff --git a/test/ruby/test_m17n_comb.rb b/test/ruby/test_m17n_comb.rb
index b5208f44f1..7d6794292b 100644
--- a/test/ruby/test_m17n_comb.rb
+++ b/test/ruby/test_m17n_comb.rb
@@ -1099,7 +1099,11 @@ class TestM17NComb < Test::Unit::TestCase
         next
       end
       if !s1.ascii_only? && !s2.ascii_only? && s1.encoding != s2.encoding
-        assert_raise(ArgumentError) { s1.scan(s2) }
+        if s1.valid_encoding?
+          assert_raise(Encoding::CompatibilityError) { s1.scan(s2) }
+        else
+          assert_raise(ArgumentError, /invalid byte sequence/) { s1.scan(s2) }
+        end
         next
       end
       if !s1.valid_encoding?
@@ -1418,7 +1422,7 @@ class TestM17NComb < Test::Unit::TestCase
           next
         end
         if !str_enc_compatible?(s1, s2)
-          assert_raise(ArgumentError, desc) { doit.call }
+          assert_raise(Encoding::CompatibilityError, desc) { doit.call }
           next
         end
         if !enccall(s1, :include?, s2)
@@ -1476,7 +1480,7 @@ class TestM17NComb < Test::Unit::TestCase
           next
         end
         if !str_enc_compatible?(s1, s2)
-          assert_raise(ArgumentError, desc) { doit.call }
+          assert_raise(Encoding::CompatibilityError, desc) { doit.call }
           next
         end
         if !enccall(s1, :include?, s2)