Setting Content-Type header for RSpec and Rails-API

A lot of frustration and variations and that's what worked for me. Rails 3.2.12 Rspec 2.10

 @request.env["HTTP_ACCEPT"] = "application/json"
 @request.env["CONTENT_TYPE"] = "application/json"
 put :update, :id => 1, "email" => "[email protected]"

wrap_parameters seems to be working declared this way

wrap_parameters User, format: :json

being used for User model

Using the new Rails v5.0.x API only settings I found that this problem with rails defaulting everything to "application/x-www-form-urlencoded" is still in issue for testing with RSpec-Rails Requests

Here is what I did to fix the problem:

Create support file at ./spec/support/json_requests.rb

Edit it to be something like this to override the behavior for all of your API only JSON requests:

module JsonRequests
  def get(*args)
    super(*json_args(*args))
  end

  def post(*args)
    super(*json_args(*args))
  end

  def update(*args)
    super(*json_args(*args))
  end

  def patch(*args)
    super(*json_args(*args))
  end

  def put(*args)
    super(*json_args(*args))
  end

  def delete(*args)
    super(*json_args(*args))
  end

  def json_args(path, params = {}, headers = {})
    [path, params.to_json, headers.merge('CONTENT_TYPE' => 'application/json')]
  end
end

RSpec.configure do |config|
  config.include JsonRequests, type: :request
end

Keep in mind that this will override all Specs within ./spec/requests so if you need to use "application/x-www-form-urlencoded" you could also include this module manually as needed in your Describe 'something' do block.

This worked for me Rails 4.0.3 and Rspec 2.14.1 if anyone is looking for more recent versions.

put '/projects/1.json', {name: 'Updated Project 1'}, {
  'HTTP_ACCEPT' => 'application/json',
  'CONTENT_TYPE' => 'application/json'
}

and

wrap_parameters Project, format: :json