How do I test my JSON API with Sinatra + rspec - api

Question

I have a post method that accepts JSON:
post '/channel/create' do
content_type :json
#data = JSON.parse(env['rack.input'].gets)
if #data.nil? or !#data.has_key?('api_key')
status 400
body({ :error => "JSON corrupt" }.to_json)
else
status 200
body({ :error => "Channel created" }.to_json)
end
As a newbie to rspec I am bewildered trying to figure out how to write a test against that POST with an acceptable JSON payload. The closest I got to is this which is woefully inaccurate but I don't seem to be asking the Google god the right questions to help me out here.
it "accepts create channel" do
h = {'Content-Type' => 'application/json'}
body = { :key => "abcdef" }.to_json
post '/channel/create', body, h
last_response.should be_ok
end
Any best practice guidance for testing APIs in Sinatra will be most appreciated also.

Answer 1

The code you've used is fine, although I would structure it slightly differently as I don't like to use it blocks the way you normally see them, I think it encourages testing of more than one aspect of a system at a time:
let(:body) { { :key => "abcdef" }.to_json }
before do
post '/channel/create', body, {'CONTENT_TYPE' => 'application/json'}
end
subject { last_response }
it { should be_ok }
I've used let because it's better than an instance variable in a before block (kudos to you for not doing that). The post is in a before block because it's not really part of the spec, but a side effect that occurs prior to what you're speccing. The subject is the response and that makes the it a simple call.
Because checking the response is ok is needed so often I put it in a shared example:
shared_examples_for "Any route" do
subject { last_response }
it { should be_ok }
end
and then call it as such:
describe "Creating a new channel" do
let(:body) { { :key => "abcdef" }.to_json }
before do
post '/channel/create', body, {'CONTENT_TYPE' => 'application/json'}
end
it_should_behave_like "Any route"
# now spec some other, more complicated stuff…
subject { JSON.parse(last_response.body) }
it { should == "" }
and because the content type changes so often, I put that in a helper:
module Helpers
def env( *methods )
methods.each_with_object({}) do |meth, obj|
obj.merge! __send__(meth)
end
end
def accepts_html
{"HTTP_ACCEPT" => "text/html" }
end
def accepts_json
{"HTTP_ACCEPT" => "application/json" }
end
def via_xhr
{"HTTP_X_REQUESTED_WITH" => "XMLHttpRequest"}
end
It's easy to add this in where it's needed by including it via the RSpec config:
RSpec.configure do |config|
config.include Helpers, :type => :request
then:
describe "Creating a new channel", :type => :request do
let(:body) { { :key => "abcdef" }.to_json }
before do
post '/channel/create', body, env(:accepts_json)
end
Having said all that, personally, I wouldn't post using JSON. HTTP POST is simple to handle, and every form and javascript library does it easily and well. Respond with JSON by all means, but don't post JSON, HTTP is a lot easier.
Edit: after writing out the Helpers bit above I realised it would be more helpful as a gem.

Answer 2

Looks like the ability to do post :update, '{"some": "json"}' was added to the internal ActionPack test_case.rb used by rspec in this commit:
https://github.com/rails/rails/commit/5b9708840f4cc1d5414c64be43c5fc6b51d4ecbf
Since you're using Sinatra I'm not sure the best way to get those changes—you might be able to upgrade ActionPack directly, or patch from the above commit.

Answer 3

If you want to look at last_response as JSON, you could try rack-test-json which makes this trivial:
expect(last_response).to be_json
expect(last_response.as_json['key']).to be == 'value'