How do you test an AJAX request with RSpec/RoR?

I'm fairly new to RoR and recently started learning BDD/Rspec for testing my application. I've been looking for a way to spec an AJAX request, but so far I haven't found much documentation on this at all.

Anyone know how to do this? I'm using rails 2.3.8, rspec 1.3.0 and mocha 0.9.8 for my stubs (which I'm also in the process of learning...)

If you're talking about testing it inside your controller specs, where you normally call

get :index

to make an HTTP request to the index action, you would instead call

xhr :get, :index

to make an XmlHttpRequest (AJAX) request to the index action using GET.

Rails 5 / 6

Since Rails 5.0 (with RSpec 3.X), try setting xhr: true like this:

get :index, xhr: true

Background

Here's the relevant code in the ActionController::TestCase. Setting the xhr flag ends up adding the following headers:

if xhr
  @request.set_header "HTTP_X_REQUESTED_WITH", "XMLHttpRequest"
  @request.fetch_header("HTTP_ACCEPT") do |k|
    @request.set_header k, [Mime[:js], Mime[:html], Mime[:xml], "text/xml", "*/*"].join(", ")
  end
end

Syntax changed a bit for Rails 5 and rspec > 3.1(i believe)

for POST requests:

post :create, xhr: true, params: { polls: { question: 'some' } }

you now need explicitely set params

for GET requests:

get :action, xhr: true, params: { id: 10 }

for rails 4 and rspec <= 3.1

xhr post :create, { polls: { question: 'some' } }

GET requests:

xhr get :show, id: 10