1 files changed, 19 insertions, 0 deletions
diff --git a/test/test_tmpdir.rb b/test/test_tmpdir.rb
index 62b4abfa1a..842b2ded90 100644
--- a/test/test_tmpdir.rb
+++ b/test/test_tmpdir.rb
@@ -2,6 +2,25 @@ require 'test/unit'
 require 'tmpdir'
 
 class TestTmpdir < Test::Unit::TestCase
+  def test_tmpdir_modifiable
+    tmpdir = Dir.tmpdir
+    assert_equal(false, tmpdir.frozen?)
+    tmpdir_org = tmpdir.dup
+    tmpdir << "foo"
+    assert_equal(tmpdir_org, Dir.tmpdir)
+  end
+
+  def test_tmpdir_modifiable_safe
+    Thread.new {
+      $SAFE = 1
+      tmpdir = Dir.tmpdir
+      assert_equal(false, tmpdir.frozen?)
+      tmpdir_org = tmpdir.dup
+      tmpdir << "foo"
+      assert_equal(tmpdir_org, Dir.tmpdir)
+    }.join
+  end
+
   def test_world_writable
     skip "no meaning on this platform" if /mswin|mingw/ =~ RUBY_PLATFORM
     Dir.mktmpdir do |tmpdir|