Any attempt to test implementation of http://tickets.opscode.com/browse/CHEF-289 show errors in main controller.
For example, absolute_url(:cookbooks) doesn't find any apprepriate route.
Other bugs of implementation:
absolute_route(:search) requires arguments to build route.
haml is not supported by chef server api.
before :authenticate_every should be not required in / endpoint.
Fixed here: https://github.com/opscode/chef/commit/5e4c1d6b8eaf8bd7841fea53d4e8b993c0451953
Thanks for reporting this one, Akzhan!