Compile assets before run rspec features test

feature_helper.rb

# spec/support/feature_helper.rb

RSpec.configure do |config|
  config.before :all do
    ENV['PRECOMPILE_ASSETS'] ||= begin
      case self.class.metadata[:type]
      when :feature, :view
        STDOUT.write "Precompiling assets..."

        system "bundle exec rake assets:precompile > /dev/null 2>&1"

        STDOUT.puts "\n Done."
        Time.now.to_s
      end
    end
  end
end