Functional testing of a JSON Rails API

Question

I'm currently building a JSON API powered by Rails/rails-api. I have a route which accepts JSON send via a PATCH request and a before filter which needs access to the raw request/JSON. For testing purposes I added following before filter to show my problem: ``` before_filter do puts "Raw Post: #{request.raw_post.inspect}" puts "Params: #{params.inspect}" end ``` The following curl request works as intended: ``` curl -X PATCH -H "Content-Type: application/json" -d '{"key":"value"}' http://localhost:3000/update # Raw Post: "{\"key\":\"value\"}" # Params: {"key"=>"value", "action"=>"update", "controller"=>"posts"} ``` However I fail testing this method, none of the following calls do work: Params included, but not as JSON transferred ``` test 'passing hash' do patch :update, { key: "value" } end # Raw Post: "key=value" # Params: {"key"=>"value", "controller"=>"posts", "action"=>"update"} ``` Params included, but again not as JSON transferred ``` test 'passing hash, setting the format' do…

Accepted Answer

This is a bug, reported by same author of this question. It is not likely to be fixed until Rails 5, or so it seems by looking at the milestone it has been assigned to.

If you land here, like me, after some hours dealing with this issue unknowing that it is really a bug, maybe you want to know that you can do that in an Integration test:

`$ rails g integration_test my_integration_test`

```
require 'test_helper'

class MyIntegrationTestTest < ActionDispatch::IntegrationTest
  setup do
    @owner = Owner.create(name: 'My name')
    @json = { name: 'name', value: 'My new name' }.to_json
  end

test "update owner passing json" do
    patch "/owners/#{@owner.id}", 
      @json,
      { 'Accept' => Mime::JSON, 'Content-Type' => Mime::JSON.to_s}

assert_response :success
    assert_equal 'application/json', response.headers['Content-Type']
    assert_not_nil assigns :owner
    assert_equal 'My new name', assigns(:owner).name
  end
end
```

Functional testing of a JSON Rails API

Solution

Problem