Ruby on Rails testing with integration_test

In my ruby on rails application when I run the following command I can't create required testing files.

rails generate integration_test named --integration-tool=rspec -s

I want to create the following files

  invoke  test_unit
  create    test/integration/named_test.rb

However, I get this message:

  invoke  rspec

I have the subsequent piece of code in my application:

  config.generators do |g|
    g.test_framework :rspec,
      fixtures: true,
      view_specs: false,
      helper_specs: false,
      routing_specs: false,
      controller_specs: false,
      request_specs: false
    g.fixture_replacement :factory_girl, dir: "spec/factories"
end

I can't see what I'm missing,

Any suggestions,

Thanks.