goroutine周りのテストコード

goroutine_test.go

package main

import(
	"fmt"
	"sync"
	"time"
	"runtime"
)

func main(){
	fmt.Printf("Start: %v\n", runtime.NumGoroutine())
	
	var wg sync.WaitGroup
	wg.Add(3)
	
	finChan := make(chan bool)
	errChan := make(chan error)
	oneChan := make(chan int)
	fiveChan := make(chan int)
	tenChan := make(chan int)
	
	go func() {
		defer fmt.Println("OK!")
		wg.Wait()
		finChan <- true
	}()
	
	go func() {
		defer wg.Done()
		time.Sleep(1 * time.Second)
		if false {
			errChan <- fmt.Errorf("error!")
			return
		}
		fmt.Println("One")
		oneChan <- 1
	}()
	
	go func() {
		defer wg.Done()
		time.Sleep(5 * time.Second)
		if false {
			errChan <- fmt.Errorf("error!")
			return
		}
		fmt.Println("Five")
		fiveChan <- 5
	}()
	
	go func() {
		defer wg.Done()
		time.Sleep(10 * time.Second)
		if false {
			errChan <- fmt.Errorf("error!")
			return
		}
		fmt.Println("Ten")
		tenChan <- 10
	}()
	
	var err error
	EVENT:
	for {
		select {
		case <-finChan:
			close(errChan)
			break EVENT
		case err = <-errChan:
			break EVENT
		case one := <-oneChan:
			fmt.Println(one)
		case five := <-fiveChan:
			fmt.Println(five)
		case ten := <-tenChan:
			fmt.Println(ten)
		}
	}
	
	if err != nil {
		fmt.Println(err.Error())
	}
	time.Sleep(10 * time.Second)
	fmt.Printf("End: %v", runtime.NumGoroutine())
}