support multi-run for ruby/test_const.rb

need to redef Constants.

test/ruby/test_const.rb

@@ -3,6 +3,13 @@
 require 'test/unit'
 
 class TestConst < Test::Unit::TestCase
+
+  setup_constants_proc = -> do
+    remove_const :TEST1  if defined? ::TestConst::TEST1
+    remove_const :TEST2  if defined? ::TestConst::TEST2
+    remove_const :Const  if defined? ::TestConst::Const
+    remove_const :Const2 if defined? ::TestConst::Const2
+
     TEST1 = 1
     TEST2 = 2
 
@@ -15,8 +22,14 @@ class TestConst < Test::Unit::TestCase
       TEST3 = 6
       TEST4 = 8
     end
+  end
+
+  define_method :setup_constants do
+    setup_constants_proc.call
+  end
 
   def test_const
+    setup_constants
     assert defined?(TEST1)
     assert_equal 1, TEST1
     assert defined?(TEST2)