thoughtbot/shoulda-context — pull request #34 by mhw (2013-10-04 22:35:48+00:00)
Title: Rails 4 doesn't load rails/init.rb

Rails 4 seems to have dropped support for rails/init.rb as a way of initialising gems. As a result shoulda-context no longer automatically loads macros from test/shoulda_macros.

The quick workaround is to add

Shoulda.autoload_macros(Rails.root)

in your test/test_helper.rb

The better solution would be to add support for Rails' Railties extension mechanism, which seems to be the supported approach now.