Add spec for nil buffer passed to Zlib::GzipReader#readpartial
Add spec for nil buffer passed to Zlib::GzipReader#readpartial

nobu/rubyspec,sgarciac/spec,ruby/spec,ruby/spec,ruby/rubyspec,eregon/rubyspec,eregon/rubyspec,sgarciac/spec,eregon/rubyspec,ruby/spec,ruby/rubyspec,sgarciac/spec,nobu/rubyspec,nobu/rubyspec