Avdi Grimm's creation, pulled from Objects on Rails

module_stubbing.rb

module ModuleStubbing
  def stubbed_modules
    @stubbed_modules ||= []
  end

  def stub_module(full_name)
    most_shallow_stubbed_module = nil

    full_name.to_s.split(/::/).inject(Object) do |context, name|
      begin
        context.const_get(name)
      rescue NameError
        most_shallow_stubbed_module ||= [context, name]
        context.const_set(name, Module.new)
      end
    end.tap { stubbed_modules << most_shallow_stubbed_module }
  end

  def cleanup_stub_modules
    stubbed_modules.each do |(context, name)|
      context.send(:remove_const, name)
    end
  end
end

RSpec.configure do |c|
  c.include ModuleStubbing
  c.after(:each) { cleanup_stub_modules }
end