If you have a Rails Engine you probably have a dummy app attached in
spec/dummy to run and manual test the engine, right?
So you can use this dummy app to have some feature tests with capybara.
The trick is to change the
RAILS_ROOT to point to the correct file.
For cucumber tests add the following into
ENV["RAILS_ROOT"] ||= File.expand_path(File.dirname(__FILE__) + '/../../spec/dummy')
For rspec tests add the following into
ENV["RAILS_ROOT"] ||= File.expand_path(File.dirname(__FILE__) + '/dummy')