I just made a patch and wanted to see if some people could verify it. It's attached to the ticket at: http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1801-testsession-and-abstractstore-delete-and-update-methods-do-not-match-in-parameter-count#ticket-1801-4
Basically, with the new SessionHash after going to rack requests, etc... TestSession.delete and .update took no parameters while AbstractStore::SessionHash was a subclass of Hash and so had a different set of update and delete methods (those from Hash). So code that called update or delete in a Test would not work in production and vice versa. This patch brings the functions into line with some deprecation warnings.