new file.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@17855 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/test_singleton.rb

@@ -0,0 +1,15 @@
+require 'test/unit'
+require 'singleton'
+
+class TestSingleton < Test::Unit::TestCase
+  class C
+    include Singleton
+  end
+
+  def test_marshal
+    o1 = C.instance
+    m = Marshal.dump(o1)
+    o2 = Marshal.load(m)
+    assert_same(o1, o2)
+  end
+end