Rails 4 - rendering JSON from a view - ruby-on-rails

Question

I'm having the worst time rendering a .json.erb file from my controller while being able to test it with RSpec. I have api_docs/index.json.erb and the following controller:
class ApiDocsController < ApplicationController
respond_to :json
def index
render file: 'api_docs/index.json.erb', content_type: 'application/json'
end
end
The explicit render file line seems unnecessary, but if I don't do that or render template: 'api_docs/index.json.erb', then I get an error about "Missing template api_docs/index". Likewise if I do have to pass the file name, it sucks even more that I have to give the exact directory--Rails should know that my ApiDocsController templates live in the api_docs directory.
If I have render file or render template, then I can visit the page and get the JSON contents of my index.json.erb file, as expected. However, this RSpec test fails:
let(:get_index) { ->{ get :index } }
...
describe 'JSON response' do
subject {
get_index.call
JSON.parse(response.body)
}
it 'includes the API version' do
subject['apiVersion'].should_not be_nil
end
end
It fails on the JSON.parse(response.body) line and if I raise response.body, it's an empty string. If I do render json: {'apiVersion' => '1.0'}.to_json in the controller, then the test passes just fine.
So, how can I always render the JSON template when I go to /api_docs (without having to put .json at the end of the URL), and in a way that works both in the browser and in my RSpec test? And can I render the template without having to have some long render call in which I pass the full path of the view?

Answer 1

Actually since you're already using respond_to :json in your controller you can use just a render method to choose your template and, as you probably know, if the template have the same name of the controller method you should be able to suppress the whole render method.
If you just remove the render line, what's the result?

Answer 2

Part of my solution was based on this answer to another question: adding defaults: {format: :json} to my routes file lets me go to /api_docs and see the JSON when the action is just def index ; end with no render. The RSpec test still fails though. The full line from my routes file: resources :api_docs, only: [:index], defaults: {format: :json}.
Thanks to this guy with the same problem and his gist, I added render_views to my describe block and got my test to pass:
describe ApiDocsController do
render_views
...
let(:get_index) { ->{ get :index } }
describe 'JSON response' do
subject {
get_index.call
JSON.parse(response.body)
}
it 'includes the API version' do
subject['apiVersion'].should_not be_nil
end
end