What should I do if I get "Could not find a JavaScript runtime." while running the test?

When I was developing Rails, I was developing using rbenv, but there was a little trouble, so I renewed my development environment.

If you run ./bin/rake test after doing bundle install, you will get the following error:

FoobarsControllerTest#test_should_get_new:
ActionView::Template::Error:cSee https://github.com/sstephenson/execjs for a list of available runtimes.
 (in/home/essehara/.rbenv/versions/2.1.4/lib/ruby/gems/2.1.0/gems/turbolinks-2.5.3/lib/assets/javascripts/turbolinks.js.coffee)
  app/views/layouts/application.html.erb:6:in`_app_views_layouts_application_html_erb_3074344629272133642_70077899278000'
  test/controllers/foobar_controller_test.rb:16:in`block in<class:FoobarsControllerTest>'

I remember that the above error did not occur in the previous environment.Why do we need execjs like this?Also, what is the fundamental solution to this?

For your information, I tried bundle install in the following rbenv environment, but I get an error using any of them:

• ruby 2.1.0
• ruby 2.2.0
• ruby 2.2.1

If there is a correct solution to this error, please let me know.