use Minitest::Unit.current_repeat_count to skip multi-run.

test/ruby/test_refinement.rb

@@ -217,8 +217,6 @@ class TestRefinement < Test::Unit::TestCase
     assert_raise(NoMethodError) { FooExtClient.public_send_b_on(foo) }
   end
 
-  DONE_TESTS = []
-
   module MethodIntegerPowEx
     refine Integer do
       def pow(*)
@@ -227,8 +225,7 @@ class TestRefinement < Test::Unit::TestCase
     end
   end
   def test_method_should_use_refinements
-    skip if DONE_TESTS.include? __method__ # giveup multi-run
-    DONE_TESTS << __method__
+    skip if Minitest::Unit.current_repeat_count > 0
 
     foo = Foo.new
     assert_raise(NameError) { foo.method(:z) }
@@ -251,8 +248,7 @@ class TestRefinement < Test::Unit::TestCase
     end
   end
   def test_instance_method_should_use_refinements
-    skip if DONE_TESTS.include? __method__ # giveup multi-run
-    DONE_TESTS << __method__
+    skip if Minitest::Unit.current_repeat_count > 0
 
     foo = Foo.new
     assert_raise(NameError) { Foo.instance_method(:z) }