diff --git a/ChangeLog b/ChangeLog
index 25cabea87e..fa26eba6bc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue May 11 21:53:18 2010  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* test/rake/test_task_arguments.rb: makes ENV empty during tests
+	  because ENV may change the behavior of Rake::TaskArguments.
+	  [ruby-core:29984]
+
 Tue May 11 09:57:05 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* eval_intern.h (rb_vm_get_sourceline): add prototype.
diff --git a/test/rake/test_task_arguments.rb b/test/rake/test_task_arguments.rb
index deb5f19ea2..d40144f3fd 100644
--- a/test/rake/test_task_arguments.rb
+++ b/test/rake/test_task_arguments.rb
@@ -3,9 +3,14 @@ require 'rake'
 
 ######################################################################
 class Rake::TestTaskArguments < Test::Unit::TestCase
+  def setup
+    @backup = ENV.to_hash
+    ENV.clear
+  end
+
   def teardown
-    ENV.delete('rev')
-    ENV.delete('VER')
+    ENV.clear
+    @backup.each {|k, v| ENV[k] = v }
   end
 
   def test_empty_arg_list_is_empty