Sinatra unit test - post with JSON body

Question

I am trying to build a unit test for a REST API I built using Sinatra. For right now I just want to test that my echo function works right. Echo uses POST and will return the exact same payload from the post. I am still new with ruby, so forgive me if I don't use the proper lingo.

Here is the code I want to test:

post '/echo' do
  request.body.read
end

This is the unit test I am trying to make:

ENV['RACK_ENV'] = 'test'
require './rest_server'
require 'test/unit'
require 'rack/test'
require 'json'

class RestServer < Test::Unit::TestCase

  def app
    Sinatra::Application
  end

  def test_check_methods
    data = '{"dataIn": "hello"}'
    response = post '/echo', JSON.parse(data)
    assert.last_response.ok?
    assert(response.body == data)
  end
end

With the above code, here is the error:

NoMethodError: undefined method `dataIn' for Sinatra::Application:Class
    /Users/barrywilliams/.rvm/gems/ruby-1.9.3-p448/gems/sinatra-1.3.4/lib/sinatra/base.rb:1285:in `block in compile!'
    /Users/barrywilliams/.rvm/gems/ruby-1.9.3-p448/gems/sinatra-1.3.4/lib/sinatra/base.rb:1285:in `each_pair'
    /Users/barrywilliams/.rvm/gems/ruby-1.9.3-p448/gems/sinatra-1.3.4/lib/sinatra/base.rb:1285:in `compile!'
    /Users/barrywilliams/.rvm/gems/ruby-1.9.3-p448/gems/sinatra-1.3.4/lib/sinatra/base.rb:1267:in `route'
    /Users/barrywilliams/.rvm/gems/ruby-1.9.3-p448/gems/sinatra-1.3.4/lib/sinatra/base.rb:1256:in `post'
    /Users/barrywilliams/.rvm/gems/ruby-1.9.3-p448/gems/sinatra-1.3.4/lib/sinatra/base.rb:1688:in `block (2 levels) in delegate'
    /Users/barrywilliams/RubymineProjects/project/rest_server_test.rb:20:in `test_check_methods'

If I try doing it without the JSON.parse, I get

NoMethodError: undefined method `key?' for "{\"dataIn\": \"hello\"}":String
/Users/barrywilliams/.rvm/gems/ruby-1.9.3-p448/gems/sinatra-1.3.4/lib/sinatra/base.rb:1265:in `route'
/Users/barrywilliams/.rvm/gems/ruby-1.9.3-p448/gems/sinatra-1.3.4/lib/sinatra/base.rb:1256:in `post'
/Users/barrywilliams/.rvm/gems/ruby-1.9.3-p448/gems/sinatra-1.3.4/lib/sinatra/base.rb:1688:in `block (2 levels) in delegate'
/Users/barrywilliams/RubymineProjects/project/rest_server_test.rb:20:in `test_check_methods'

If I try doing it where data = 'hello', then I get the same undefined method 'key?' error

I've tried this suggestion, with no success: http://softwareblog.morlok.net/2010/12/18/testing-post-with-racktest/ I get an error saying that post only takes 2 arguments, not 3.

So, in summary, I need to be able to make a call, have the code I'm testing receive the call and return a response, then I need to be able to read that response and verify it was the original data. Right now it looks like it's getting stuck at just making the call.

I think you should be making an integration test not a unit test for this. A unit test is for testing classes rather than for testing requests. Maybe this question will help? http://stackoverflow.com/questions/8013770/rspec-rails-3-1-integration-test-how-to-send-post-request-headers-for-mobile-h — jamesc, Aug 26 '13 at 17:26
Have you tried just posting the data structure? `post 'echo', {"dataIn" => "hello"}` — Lars Haugseth, Aug 26 '13 at 17:41

score 9 · Answer 1 · answered Apr 18 '14 at 18:23

I did a thing a little similar, it might help you :

The application post definition :

post '/' do
    data = JSON.parse request.body.read.to_s
    "Hello !\n#{data.to_s}"
end

The .to_s is necessary, else the conversions will not be exactly the same :-/

Then on the test file :

class RootPostTest < Test::Unit::TestCase
    include Rack::Test::Methods
    def app
        Sinatra::Application
    end

    def test_return_the_parameters
        data = {
            'reqID' => 1,
            'signedReqID' => "plop",
            'cert' => "mycert"
        }
        post '/', data.to_json, "CONTENT_TYPE" => "application/json"
        assert last_response.ok?
        body_espected = "Hello !\n#{JSON.parse(data.to_json).to_s}"
        assert_equal last_response.body, body_espected
    end
end

Hope it helped you.

score 3 · Answer 2 · edited May 23 '17 at 10:30

Rack Test will give you back the response body in last_response.body, no need to save it to a variable. You're also not echoing back what you've sent - data in the code you've given is JSON, but you converted it to a hash and posted that, so it's not going to match what comes back. Either send JSON, or convert it to JSON in the Sinatra route if you want to do that (see https://stackoverflow.com/a/12138793/335847 for more).

In the Sinatra app:

require 'json'

post '/echo' do
  # Don't use request.body.read as you're not posting JSON
  params.to_json
end

and in the test file:

def test_check_methods
  data = '{"dataIn": "hello"}'
  post '/echo', JSON.parse(data)
  assert.last_response.ok?
  assert(last_response.body == data)
end

If you do end up wanting to post JSON (which I think is usually not a good idea if it's easy to convert or already have the data as a hash) then use :provides => "json" as a condition to the route, and consider using Rack::Test::Accepts to make life easier writing the test for that (note: that's a shameless plug for a gem I wrote;)

Sinatra unit test - post with JSON body

2 Answers2