I've just installed konacha on Rails 4.1 application and it turns out that both rake tasks to run or serve konacha don't work correctly in default (development) Rails environment. The reason for both is exactly the same:

ActionView::Template::Error: Asset filtered out and will not be served: add Rails.application.config.assets.precompile += %w( xxx_spec.js ) to config/initializers/assets.rb and restart your server

Local solution is just changing the env:

RAILS_ENV=test bundle exec rake konacha:run

So maybe konacha should set env to test by default, just like it is in default RSpec spec_helper?