remove the warning when testing whiny_nil

Author: dmathieu

activesupport/test/whiny_nil_test.rb

@@ -33,11 +33,10 @@ def test_array
   end
 
   def test_id
-    nil.stubs(:object_id).returns(999)
     nil.id
   rescue RuntimeError => nme
     assert_no_match(/nil:NilClass/, nme.message)
-    assert_match(/999/, nme.message)
+    assert_match(Regexp.new(nil.object_id.to_s), nme.message)
   end
 
   def test_no_to_ary_coercion