```ruby
require 'spec_helper'
require 'rack_spec_helper'
require 'tic_tac_toe/rack_shell'

describe TicTacToe::RackShell do

  it 'can receive an index/root GET request' do
    app = TicTacToe::RackShell.new_shell
    req = Rack::MockRequest.new(app)
    response = req.get("/")
    expect(response.successful?).to be_truthy
  end

end
```

Change rack spec to use rack-test library
user
```ruby
require 'spec_helper'
require 'rack_spec_helper'
require 'tic_tac_toe/rack_shell'

describe TicTacToe::RackShell do
  include Rack::Test::Methods

  def app
    TicTacToe::RackShell.new_shell
  end

  it 'can receive an index/root GET request' do
    get '/'
    expect(last_response.successful?).to be_truthy
  end

end
```
assistant