diff --git a/ChangeLog b/ChangeLog
index f5610bf477..7d4265a8e5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Oct  6 12:38:36 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* lib/test/unit/assertions.rb (Test::Assertions#assert_nothing_raised): 
+	  should take optional message argument.
+
 Mon Oct  6 12:18:23 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* string.c (rb_str_comparable): string comparison should be
diff --git a/lib/test/unit/assertions.rb b/lib/test/unit/assertions.rb
index 6c29b78096..ee973dc58e 100644
--- a/lib/test/unit/assertions.rb
+++ b/lib/test/unit/assertions.rb
@@ -40,7 +40,7 @@ module Test::Unit
     tu_deprecate :assert_not_nil,        :refute_nil            # 2009-06-01
     tu_deprecate :assert_not_same,       :refute_same           # 2009-06-01
 
-    def assert_nothing_raised _ = :ignored                      # 2009-06-01
+    def assert_nothing_raised _ = :ignored, msg = nil           # 2009-06-01
       self.class.tu_deprecation_warning :assert_nothing_raised
       self._assertions += 1
       yield