How to avoid global constant in the specs

class_definition_in_specs.rb

require 'spec_helper'

describe "Wow Coins" do
  let(:klasz_class) do
    Class.new do
      attr_reader :title

      def initialize(properties)
        @title = properties[:title]
      end
    end
  end

  describe "public stuff" do
    subject { !!defined?(Klasz) }

    context "when I stub the contant" do
      before do
        stub_const("Klasz", klasz_class)
      end

      it { is_expected.to be(true) }
    end

    context "when I DO NOT stub the contant" do
      it { is_expected.to be(false) }
    end
  end
end