simple_testcase.go

package main

import "net"
import "time"

const (
	protocol = "tcp"
	addr     = ":6502"
)

func main() {
	listener, err := net.Listen(protocol, addr)
	if err != nil {
		panic(err)
	}

	go func() {
		for {
			c, err := listener.Accept()
			if err != nil {
				return
			}
			c.Close()
		}
	}()

	// trigger the race by giving the above goroutine time to start
	time.Sleep(time.Second)

	listener.Close()

	_, err = net.Listen(protocol, addr)
	if err != nil {
		panic(err)
	}
}