http://vladimir-vg.github.com/blog/2012/03/14/test-runner-watcher-for-go/

watcher.go

package main

import "log"
import "os"
import "regexp"
import "os/exec"
import "exp/inotify"

func runTests() {
	cmd := exec.Command("go", "test")
	cmd.Stdout = os.Stdout
	if err := cmd.Run(); err != nil {
		log.Println(err)
		notifySystem("go test failed")
	}
}

// probably will work only for Ubuntu
func notifySystem(message string) {
	cmd := exec.Command("notify-send", message)
	if err := cmd.Run(); err != nil {
		log.Fatal(err)
	}
}

func setupWatcher() *inotify.Watcher {
	watcher, err := inotify.NewWatcher()
	if err != nil {
		log.Fatal(err)
	}
	
	err = watcher.AddWatch(".", inotify.IN_MODIFY)
	if err != nil {
		log.Fatal(err)
	}
	
	return watcher
}
 
func main() {
	watcher := setupWatcher()
	
	runTests()
	for {
		select {
		case ev := <-watcher.Event:
			matched, err := regexp.MatchString(".*\\.go", ev.Name)
			if err != nil {
				log.Fatal(err)
			}
			
			if matched {
				// On my machine it always raised two events
				// ignore second, prevent twice tests run.
				// Probably it's depends of test editor.
				// If so, feel free to
				// remove line above:
				<-watcher.Event
				
				runTests()
			}
		case err := <-watcher.Error:
			log.Println("error:", err)
		}
	}
}