add more test coverage for [ruby-core:63136] [Bug #9934]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46414 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-06-13

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46415 b2dd03c8-39d4-4d8f-98ff-823fe69b080e