mock

You want to use a mock when you're testing a behaviour of one of your methods that interacts with some outside world service (eg. an FTP server).

it "should login to ftp server" do ftp = mock('Ftp server', :null_object => true) Net::FTP.should_receive(:new).and_return(ftp) ftp.should_receive(:login).with('username', 'password') some_obj.connect end

def connect session = Net::FTP.new('server.com') session.login('username', 'password') session.close end