In Rails, how do you functional test a Javascript response format?

Question

If your controller action looks like this:

respond_to do |format|
  format.html { raise \'Unsupported\' }
  format.js # index.js.erb
end

and yo

Answer 1

with rspec:

it "should render js" do
  xhr :get, 'index'
  response.content_type.should == Mime::JS
end

and in your controller action:

respond_to do |format|
  format.js
end