rspec testing a controller method, calling a lib wrapper that makes an API call

In the application, the user can fill in 3 fields (and 1 hidden field) and click 'load response', and this will make an ajax API call to an external API. The call to the external API is in a wrapper in lib. This wrapper stores additional required fields that the user doesn't need to enter, but are required by the API.

I've seen a few other posts about testing API calls, but I'm stumped on comparing them to this one and learning something from it, because of that extra wrapper.

In the view:

data = ->
  string_ssid = '#{@bar.ssID}'
  {
    approval_code: $('#approval_code').val()
    rejection_code: $('#rejection_code').val()
    rejection_message: $('#rejection_message').val()
    ssid: string_ssid
  }

ajax_call = ->
  $('#load_response').on 'click', ->
    $.ajax
      url: '/fooview/api_response'
      data: data()
      success: (d) ->
        $('#api_response').html '<p>' + JSON.stringify(d) + '</p>'
        return
      error: (d, status, e) ->
        $('#api_response').html '<p>Error: ' + e + ', ' + status + '</p>'
        return
    return
  return

Routes:

get '/baz/api_response', to: 'baz#api_response'

Controller:

  def api_response
    render json: BazWrapper.get_api_response(params)
  end

Wrapper:

module BazWrapper

  @base_url = Enviro.get(:foo) + '/message/json'

  def self.get_api_response(params)

    query_values = {
    api_key: Enviro.get(:foo, :api_key),
    approval_code: params[:approval_code],
    rejection_code: params[:rejection_code],
    rejection_message: params[:rejection_message],
    ssid: params[:ssid],
    (..other required params hard-wired..)
  }

  HTTParty.post(
    URI.encode(@base_url),
    query: query_values
    )
  end
end