Why does Ruby open-uri's open return a StringIO in my unit test, but a FileIO in my controller?

Question

I inherited a Rails 2.2.2 app that stores user-uploaded images on Amazon S3. The attachment_fu-based Photo model offers a rotate method that uses <

Answer 1

Now OpenURI::Buffer::StringMax can be set directly:

require 'open-uri'
OpenURI::Buffer::StringMax = 0

but with a warning:

warning: already initialized constant OpenURI::Buffer::StringMax