testing a doorkeeper token request via a password grant

authentication_spec.rb

require 'rails_helper'

RSpec.describe '/oauth/', type: :request do
  let(:application) { create(:doorkeeper_application, confidential: false) }
  let(:user) { create(:user, email: 'joe@example.com', password: "PASSWORD") }
  let(:valid_params) do
    {
      username: user.email,
      password: "PASSWORD",
      grant_type: 'password',
      client_id: application.uid,
    }
  end

  describe '#POST /oauth/token/' do
    context 'with valid params' do
      it 'returns a token' do
        post '/oauth/token', params: valid_params, as: :json
        expect(response).to have_http_status :ok
        response_object = JSON.parse(response.body)
        expect(response_object).to have_key 'access_token'
      end
    end
  end
end