test_stringio.rb: test_initialize
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53378 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_stringio.rb: test_initialize
StringIO#initialize. [ruby-core:72585] [Feature #11920]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53378 b2dd03c8-39d4-4d8f-98ff-823fe69b080e