Runtime exposure does not work about grape-entity HOT 6 CLOSED

  1) V1::Users GET /api/v1/users/:id/unconfirmed_tasks returns Tasks
     Failure/Error: get "/api/v1/users/#{ user.id }/unconfirmed_tasks"
     ArgumentError:
       ArgumentError
     # ./spec/api/users_spec.rb:38:in `block (3 levels) in <top (required)>'

module V1
  module Entities

    class Tasks < Grape::Entity
      expose :id, :description, :project_id, :project_url
    end

    def project_url
      'http://db.no/'
    end

  end
end

describe V1::Users do

  describe 'GET /api/v1/users/:id/unconfirmed_tasks', focus: true do
    it 'returns Tasks' do
      get "/api/v1/users/#{ user.id }/unconfirmed_tasks"  # Line 38
      array.first['project_url'].should eq 'http://db.no/'
    end
  end