server_manager.rb

class ServerManager
  attr_reader :path, :thread, :pid

  def initialize(path)
    @path = path
  end

  def run
    return if running?
    @pid = Process.spawn "ruby", path
  end

  def kill
    return unless running?
    Process.kill :INT, pid
  ensure
    @pid = nil
  end

  def running?
    pid && Process.getpgid(pid)
  rescue Errno::ESRCH
    puts "\e[36mNOT RUNNING\e[0m"
    return false
  end
end

def title(title)
  puts "", "", "\e[34m===== #{title} =====\e[39m"
end

path    = File.expand_path("server.rb", __dir__)
manager = ServerManager.new(path)

title "STARTING"
manager.run
sleep 2

title "REQUEST SHOULD WORK"
system "curl localhost:9292/hello"

title "KILLING"
manager.kill

title "REQUEST SHOULD NOT WORK"
system "curl localhost:9292/hello"

title "STARTING"
manager.run
sleep 2

title "SHUTTING IT DOWN"
system "curl localhost:9292/shutdown"

title "REQUEST SHOULD NOT WORK"
system "curl localhost:9292/hello"

title "STARTING"
manager.run
sleep 2

title "REQUEST SHOULD WORK"
system "curl localhost:9292/hello"

manager.kill