* Add tests and specs. See ruby/spec#401. Patch by Yuta Iwama and Shintaro Morikawa. [ruby-core:80153] [Bug #13315] [Fix GH-1560] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58890 b2dd03c8-39d4-4d8f-98ff-823fe69b080e