diff --git a/ChangeLog b/ChangeLog
index 59f28ca57c..b2ea6937a5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Mar 15 10:31:40 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* test/ruby/test_arity.rb (TestArity#err_mess): use assert_raise.
+
 Thu Mar 15 07:03:52 2012  Eric Hodel  <drbrain@segment7.net>
 
 	* vm_eval.c (check_funcall):  Raise ArgumentError if respond_to?
diff --git a/test/ruby/test_arity.rb b/test/ruby/test_arity.rb
index 2d84330ffc..18ef9b2d03 100644
--- a/test/ruby/test_arity.rb
+++ b/test/ruby/test_arity.rb
@@ -3,16 +3,16 @@ require 'test/unit'
 class TestArity < Test::Unit::TestCase
   def err_mess(method_proc = nil, argc = 0)
     args = (1..argc).to_a
-    case method_proc
+    err = assert_raise(ArgumentError) do
+      case method_proc
       when nil
         yield
       when Symbol
         method(method_proc).call(*args)
       else
         method_proc.call(*args)
+      end
     end
-    fail "Expected ArgumentError to be raised"
-  rescue ArgumentError => err
     s = err.to_s
     assert s =~ /wrong number of arguments \((.*)\)/, "Unexpected ArgumentError's message: #{s}"
     $1
diff --git a/test/ruby/test_object.rb b/test/ruby/test_object.rb
index 271ab600a2..d63886a81e 100644
--- a/test/ruby/test_object.rb
+++ b/test/ruby/test_object.rb
@@ -471,11 +471,11 @@ class TestObject < Test::Unit::TestCase
       end
     end
 
-    e = assert_raises(ArgumentError, '[bug:6000]') do
+    e = assert_raise(ArgumentError, '[bug:6000]') do
       [[p]].flatten
     end
 
-    assert_equal('respond_to? must accept 1 or 2 arguments (requires 3)',                        e.message)
+    assert_equal('respond_to? must accept 1 or 2 arguments (requires 3)', e.message)
   end
 
   def test_method_missing_passed_block
diff --git a/test/ruby/test_require.rb b/test/ruby/test_require.rb
index de99fbdff4..58cf241db5 100644
--- a/test/ruby/test_require.rb
+++ b/test/ruby/test_require.rb
@@ -7,7 +7,7 @@ require 'tmpdir'
 class TestRequire < Test::Unit::TestCase
   def test_load_error_path
     filename = "should_not_exist"
-    error = assert_raises(LoadError) do
+    error = assert_raise(LoadError) do
       require filename
     end
     assert_equal filename, error.path
diff --git a/test/ruby/test_thread.rb b/test/ruby/test_thread.rb
index f7b33c30ec..16af922e98 100644
--- a/test/ruby/test_thread.rb
+++ b/test/ruby/test_thread.rb
@@ -137,7 +137,7 @@ class TestThread < Test::Unit::TestCase
 #    mutex = Mutex.new
 #    cv = ConditionVariable.new
 #
-#    assert_raises(fatal) {
+#    assert_raise(fatal) {
 #      mutex.lock
 #      cv.wait mutex
 #      mutex.unlock