How do I create an rspec test that validates a JSON response?

I have a Groups Controller with a method def inbox.

If the user is a group member then inbox returns a JSON object.

If the user is not a member, then inbox should redirect thanks to CanCan permissions.

How do I write an rspec to test these two use cases?

Current spec:

require 'spec_helper'

describe GroupsController do
  include Devise::TestHelpers

  before (:each) do
    @user1 = Factory.create(:user)
    @user1.confirm!
    sign_in @user1
    @group = Factory(:group)
    @permission_user_1 = Factory.create(:permission, :user => @user1, :creator_id => @user1.id, :grou开发者_开发问答p => @group)
  end

  describe "GET inbox" do
    it "should be successful" do
      get inbox_group_path(@group.id), :format => :json
      response.should be_success
    end
  end
end

Routes:

inbox_group GET /groups/:id/inbox(.:format) {:controller=>"groups", :action=>"inbox"}

Routes File:

resources :groups do
  member do
    get 'vcard', 'inbox'
  end
  ....
end

This is how I do this:

describe "GET index" do
  it "returns correct JSON" do
    # @groups.should have(2).items
    get :index, :format => :json
    response.should be_success
    body = JSON.parse(response.body)
    body.should include('group')
    groups = body['group']
    groups.should have(2).items
    groups.all? {|group| group.key?('customers_count')}.should be_true
    groups.any? {|group| group.key?('customer_ids')}.should be_false
  end
end

I'm not using cancan, therefore I cannot help with this part.

Sometimes it might be good enough to verify if response contains valid JSON and to show actual response otherwise, here is an example:

it 'responds with JSON' do
  expect {
    JSON.parse(response.body)
  }.to_not raise_error, response.body
end

Try this:

_expected = {:order => order.details}.to_json
response.body.should == _expected

I think the first thing you want to do is to check that the response is of the correct type, i.e. that it has the Content-Type header set to application/json, something along the lines of:

it 'returns JSON' do
  expect(response.content_type).to eq(Mime::JSON)
end

Then, depending on your case, you might want to check whether the response can be parsed as JSON, like wik suggested:

it 'responds with JSON' do
  expect {
    JSON.parse(response.body)
  }.to_not raise_error
end

And you could merge the above two into a single test if you feel like two tests for checking JSON response validity are too much.

To assert JSON you can do this too:

ActiveSupport::JSON.decode(response.body).should == ActiveSupport::JSON.decode(
  {"error" => " An email address is required "}.to_json
)

This blog gives some more ideas.