Problem
Your old tests with shoulda are written using the old style should_have, should_belong, etc, which are now deprecated.
Solution
The new style of writing shoulda unit tests is should have, should belong_to etc. All the new macros can be found here
Problem
You are trying to use shoulda with factory_girl but you are getting the above error:
NameError: uninitialized constant UserTest::Factory
Solution
Insert the following to your config/environments/test.rb
config.gem 'shoulda', :lib => 'shoulda'
install the gem with:
sudo gem install shoulda
add the following to your test/test_helper.rb
require 'factory_girl'
require "factories"
in your test use the new syntax without the underscore, as in:
should belong_to(:model)