common/daemon: experiment with the test/synctest package

common/daemon/root_test.go

@@ -6,7 +6,7 @@ package daemon
 import (
 	"errors"
 	"testing"
-	"time"
+	"testing/synctest"
 
 	"gopkg.in/tomb.v2"
 
@@ -71,6 +71,7 @@ func TestStop(t *testing.T) {
 }
 
 func TestTombTracking(t *testing.T) {
+	synctest.Test(t, func(t *testing.T) {
 		var tomb tomb.Tomb
 		r := reporter.NewMock(t)
 		c, err := New(r)
@@ -91,7 +92,7 @@ func TestTombTracking(t *testing.T) {
 			}
 			return nil
 		})
-	time.Sleep(10 * time.Millisecond) // should be runtime.Gosched()
+		synctest.Wait()
 
 		select {
 		case <-tomb.Dying():
@@ -104,7 +105,7 @@ func TestTombTracking(t *testing.T) {
 
 		close(ch)
 		tomb.Wait()
-	time.Sleep(10 * time.Millisecond) // should be runtime.Gosched(), but this is not enough
+		synctest.Wait()
 		select {
 		case <-c.Terminated():
 			// OK
@@ -113,4 +114,5 @@ func TestTombTracking(t *testing.T) {
 		}
 
 		c.Stop()
+	})
 }