fix a test for debugging.

* test/rdoc/test_rdoc_markup_pre_process.rb: show
  `RDoc::Markup::PreProcess.post_processors` as a failure message
  for debugging.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61408 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/rdoc/test_rdoc_markup_pre_process.rb

@@ -29,7 +29,8 @@ class TestRDocMarkupPreProcess < RDoc::TestCase
   def test_class_post_process
     RDoc::Markup::PreProcess.post_process do end
 
-    assert_equal 1, RDoc::Markup::PreProcess.post_processors.length
+    assert_equal 1, RDoc::Markup::PreProcess.post_processors.length,
+                 proc{RDoc::Markup::PreProcess.post_processors.inspect}
   end
 
   def test_include_file