diff --git a/ChangeLog b/ChangeLog
index 214a5690a8..f26b3f783b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Mar 13 12:29:07 2015  Tanaka Akira  <akr@fsij.org>
+
+	* test/readline/test_readline.rb: Restore environment variables:
+	  COLUMNS LINES
+
 Fri Mar 13 11:37:46 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/fiddle/extconf.rb: needs --enable-shared when linked to
diff --git a/test/readline/test_readline.rb b/test/readline/test_readline.rb
index 0c50a99bc9..89d72b560f 100644
--- a/test/readline/test_readline.rb
+++ b/test/readline/test_readline.rb
@@ -9,8 +9,10 @@ end
 
 class TestReadline < Test::Unit::TestCase
   INPUTRC = "INPUTRC"
+  SAVED_ENV = %w[COLUMNS LINES]
 
   def setup
+    @saved_env = ENV.values_at(*SAVED_ENV)
     @inputrc, ENV[INPUTRC] = ENV[INPUTRC], IO::NULL
   end
 
@@ -24,6 +26,7 @@ class TestReadline < Test::Unit::TestCase
     end
     Readline.input = nil
     Readline.output = nil
+    SAVED_ENV.each_with_index {|k, i| ENV[k] = @saved_env[i] }
   end
 
   if !/EditLine/n.match(Readline::VERSION)