diff --git a/ChangeLog b/ChangeLog
index 029258d919..7e37679005 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Jan 17 14:43:01 2016  Kuniaki IGARASHI  <igaiga@gmail.com>
+
+	* test/ruby/test_env.rb: [Fix GH-1201]
+	  * Extract test code for ENV#keep_if from ENV#select_bang
+	  * Add a test case for ENV#select_bang,keep_if
+
 Sun Jan 17 14:42:25 2016  Kuniaki IGARASHI  <igaiga@gmail.com>
 
 	* test/ruby/test_env.rb: [Fix GH-1201]
diff --git a/test/ruby/test_env.rb b/test/ruby/test_env.rb
index 9fe85fb190..7224d572ec 100644
--- a/test/ruby/test_env.rb
+++ b/test/ruby/test_env.rb
@@ -212,6 +212,10 @@ class TestEnv < Test::Unit::TestCase
     ENV.each_pair {|k, v| h2[k] = v }
     assert_equal(h1, h2)
 
+    assert_nil(ENV.select! {|k, v| IGNORE_CASE ? k.upcase != "TEST" : k != "test" })
+  end
+
+  def test_keep_if
     h1 = {}
     ENV.each_pair {|k, v| h1[k] = v }
     ENV["test"] = "foo"
@@ -219,6 +223,8 @@ class TestEnv < Test::Unit::TestCase
     h2 = {}
     ENV.each_pair {|k, v| h2[k] = v }
     assert_equal(h1, h2)
+
+    assert_equal(ENV, ENV.keep_if {|k, v| IGNORE_CASE ? k.upcase != "TEST" : k != "test" })
   end
 
   def test_values_at