check_closed_channel.go

package main

import (
	"fmt"
	"time"
)

func main() {
	test(1)
	test(2)
}

func test(n int) {
	fmt.Println("TEST", n)
	
	done := make(chan bool)
	go func() {
		<-time.After(100 * time.Millisecond)
		select {
		case <-done:
			fmt.Println("channel closed")
		default:
			done <- true
			fmt.Println("channel not closed, writing to channel")
		}
		fmt.Println("goroutine finished")

	}()
	switch n {
	case 1:
		fmt.Println("closing channel")
		close(done)
	case 2:
		fmt.Println("reading from channel")
		<-done
	}

	<-time.After(200 * time.Millisecond)
	fmt.Println("test finished")
}

Test it on The Go Playground: https://play.golang.org/p/in60aXGnagU