Example output:

our Gemfile lists the gem gettext (~> 2.0) more than once.
You should probably keep only one of them.
While it's not a problem now, it could cause errors if you change the version of just one of them later.
Your Gemfile lists the gem locale (<= 2.0.9) more than once.
You should probably keep only one of them.
While it's not a problem now, it could cause errors if you change the version of just one of them later.
Your Gemfile lists the gem minitest (~> 4.7) more than once.
You should probably keep only one of them.
While it's not a problem now, it could cause errors if you change the version of just one of them later.
Your Gemfile lists the gem gettext_i18n_rails_js (>= 0.0.8) more than once.
You should probably keep only one of them.
While it's not a problem now, it could cause errors if you change the version of just one of them later.
rake aborted!
Don't know how to build task 'jenkins:setup:minitest'
/var/lib/workspace/workspace/test_katello_core/database/postgresql/ruby/1.9.3/plugin/lib/katello/tasks/jenkins.rake:7:in `block (2 levels) in <top (required)>'
/usr/local/rvm/gems/ruby-1.9.3-p392@test_katello_core-2/bin/ruby_executable_hooks:15:in `eval'
/usr/local/rvm/gems/ruby-1.9.3-p392@test_katello_core-2/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => jenkins:katello
(See full trace by running task with --trace)