How to test Controller post :create of JSON api on rails using rspec?

Question

I have been tearing my hair trying to make the test to pass. I have a JSON API that looks like this:

{
  \"data\": [
    {
      \"id\": \"b99f8173-0492-457f         


        

Answer 1

In RSpec you never* need to explicitly format the params.

post :create, params: { foo: 'bar' }, format: :json

This will properly format the hash { foo: 'bar' } as JSON in the request body.

To create a hash which matches the JSONAPI.org structure you can create a helper:

# support/api_spec_helper.rb
module APISpecHelper
  def to_json_api(model)
    {
      data: {
        type: ActiveModel::Naming.plural(model),
        attributes: model.attributes
      }.tap do |hash| 
        hash[:id] = model.id if model.persisted?
      end
    }
  end
end

You can also use the JSONAPI-RB gem or ActiveModel::Serializers to constuct/deconstruct JSONAPI responses/params.

---

require 'rails_helper'
require 'api_spec_helper'

RSpec.request "Manufacturer organizations" do 

  include APISpecHelper

  describe "POST '/manufacturer_organizations'" do
    let(:valid_params) do
      to_json_api(FactoryGirl.build(:manufacturer_organization))
    end
    let(:invalid_params) do
      to_json_api(ManufacturerOrganization.new(
        foo: 'bad_value'
      ))
    end

    describe "with valid attributes" do
      it "creates a manufacturer organization" do
        expect do
          post '/manufacturer_organizations', params: valid_params, format: :json
        end.to change(ManufacturerOrganization, :count).by(+1)
      end

      it "has the correct response" do
        post '/manufacturer_organizations', params: valid_params, format: :json
        expect(response).to have_status :created
        expect(response.headers[:location]).to eq(
          manufacturer_organization_path(ManufacturerOrganization.last)
        )
      end
    end

    describe "with valid attributes" do
      it "does not create a manufacturer organization" do
        expect do
          post '/manufacturer_organizations', params: invalid_params, format: :json
        end.to_not change(ManufacturerOrganization, :count)
      end

      it "has the correct response" do
        post '/manufacturer_organizations', params: invalid_params, format: :json
        expect(response).to have_status :unproccessable_entity
      end
    end
  end
end

Returning the correct status codes.

Returning the correct response codes is pretty simple:

def create
  @resource = Resource.create(some_params)
  if @resource.save
    # you can respond by pointing at the newly created resource but with no body
    head :created, location: @resource
    # or 
    render json: @resource, 
           status: :created, 
           location: @resource
  else
    render json: { errors: @resource.errors.full_messages }, 
           status: :unprocessable_entity
  end
end

If a POST request did not include a Client-Generated ID and the requested resource has been created successfully, the server MUST return a 201 Created status code.
http://jsonapi.org/format/#crud

Other Responses
A server MAY respond with other HTTP status codes.
A server MAY include error details with error responses.

The commonly accepted practice is to use 422 - Unprocessable Entity for validation errors.

One small concern is that you should use a serializer to give the correct JSON response and also serialize the correct error objects.