diff --git a/file_system/file_system.go b/file_system/file_system.go
index 154f2d464..d9e3e20a9 100644
--- a/file_system/file_system.go
+++ b/file_system/file_system.go
@@ -159,6 +159,7 @@ func (fs *FileSystem) Update(nodePath string, value string, expireTime time.Time
 	}
 
 	if expireTime != Permanent {
+		n.ExpireTime = expireTime
 		go n.Expire()
 		e.Expiration = &n.ExpireTime
 		e.TTL = int64(expireTime.Sub(time.Now()) / time.Second)
diff --git a/file_system/file_system_test.go b/file_system/file_system_test.go
index 16666f614..3956df0cd 100644
--- a/file_system/file_system_test.go
+++ b/file_system/file_system_test.go
@@ -55,7 +55,7 @@ func TestUpdateFile(t *testing.T) {
 	_, err := fs.Create("/foo/bar", "bar", Permanent, 1, 1)
 
 	if err != nil {
-		t.Fatalf("cannot update %s=bar [%s]", "/foo/bar", err.Error())
+		t.Fatalf("cannot create %s=bar [%s]", "/foo/bar", err.Error())
 	}
 
 	_, err = fs.Update("/foo/bar", "barbar", Permanent, 2, 1)
@@ -73,6 +73,84 @@ func TestUpdateFile(t *testing.T) {
 	if e.Value != "barbar" {
 		t.Fatalf("expect value of %s is barbar [%s]", "/foo/bar", e.Value)
 	}
+
+	// create a directory, update its ttl, to see if it will be deleted
+
+	_, err = fs.Create("/foo/foo", "", Permanent, 3, 1)
+
+	if err != nil {
+		t.Fatalf("cannot create dir [%s] [%s]", "/foo/foo", err.Error())
+	}
+
+	_, err = fs.Create("/foo/foo/foo1", "bar1", Permanent, 4, 1)
+
+	if err != nil {
+		t.Fatal("cannot create [%s]", err.Error())
+	}
+	
+	_, err = fs.Create("/foo/foo/foo2", "", Permanent, 5, 1)
+	if err != nil {
+		t.Fatal("cannot create [%s]", err.Error())
+	}
+	
+	_, err = fs.Create("/foo/foo/foo2/boo", "boo1", Permanent, 6, 1)
+	if err != nil {
+		t.Fatal("cannot create [%s]", err.Error())
+	}
+
+	expire := time.Now().Add(time.Second*2)
+	_, err = fs.Update("/foo/foo", "", expire, 7, 1)
+	if err != nil {
+		t.Fatalf("cannot update dir [%s] [%s]", "/foo/foo", err.Error())
+	}
+
+	// sleep 50ms, it should still reach the node
+	time.Sleep(time.Microsecond*50)
+	e, err = fs.Get("/foo/foo", true, 7, 1)
+	
+	if err != nil || e.Key != "/foo/foo" {
+		t.Fatalf("cannot get dir before expiration [%s]", err.Error())
+	}
+
+	if e.KVPairs[0].Key != "/foo/foo/foo1" || e.KVPairs[0].Value != "bar1" {
+		t.Fatalf("cannot get sub node before expiration [%s]", err.Error())
+	}
+
+	if e.KVPairs[1].Key != "/foo/foo/foo2" || e.KVPairs[1].Dir != true {
+		t.Fatalf("cannot get sub dir before expiration [%s]", err.Error())
+	}
+
+	/*if e.KVPairs[2].Key != "/foo/foo/foo2/boo" || e.KVPairs[2].Value != "boo1" {
+		t.Fatalf("cannot get sub node of sub dir before expiration [%s]", err.Error())
+	}*/
+
+	// wait for expiration
+	time.Sleep(time.Second*3)
+	e, err = fs.Get("/foo/foo", true, 7, 1)
+	
+	if err == nil {
+		t.Fatal("still can get dir after expiration [%s]")
+	}
+
+	_, err = fs.Get("/foo/foo/foo1", true, 7, 1)
+	if err == nil {
+		t.Fatal("still can get sub node after expiration [%s]")
+	}
+
+	_, err = fs.Get("/foo/foo/foo2", true, 7, 1)
+	if err == nil {
+		t.Fatal("still can get sub dir after expiration [%s]")
+	}
+
+	_, err = fs.Get("/foo/foo/foo2/boo", true, 7, 1)
+	if err == nil {
+		t.Fatalf("still can get sub node of sub dir after expiration [%s]", err.Error())
+	}
+
+	
+	
+	
+	
 }
 
 func TestListDirectory(t *testing.T) {
@@ -181,23 +259,30 @@ func TestExpire(t *testing.T) {
 		t.Fatalf("can get the node after expiration time")
 	}
 
+	// test if we can reach the node before expiration
+	expire = time.Now().Add(time.Second)
 	fs.Create("/foo", "bar", expire, 1, 1)
 
 	time.Sleep(time.Millisecond * 50)
 	_, err = fs.InternalGet("/foo", 1, 1)
 
-	if err == nil {
-		t.Fatalf("can get the node after expiration time")
+	if err != nil {
+		t.Fatalf("cannot get the node before expiration", err.Error())
 	}
 
 	expire = time.Now().Add(time.Second)
-
+	
 	fs.Create("/foo", "bar", expire, 1, 1)
-	fs.Delete("/foo", false, 1, 1)
+	_, err = fs.Delete("/foo", false, 1, 1)
+
+	if err != nil {
+		t.Fatalf("cannot delete the node before expiration", err.Error())
+	}
+	
 
 }
 
-func TestTestAndSet(t *testing.T) {
+func TestTestAndSet(t *testing.T) { // TODO prevValue == nil ?
 	fs := New()
 	fs.Create("/foo", "bar", Permanent, 1, 1)
 
@@ -228,29 +313,73 @@ func TestTestAndSet(t *testing.T) {
 	if e.PrevValue != "car" || e.Value != "bar" {
 		t.Fatalf("[%v/%v] [%v/%v]", e.PrevValue, "car", e.Value, "bar")
 	}
+
+	//e, err = fs.TestAndSet("/foo", )
 }
 
-func TestWatchRemove(t *testing.T) {
+func TestWatch(t *testing.T) {
 	fs := New()
-	fs.Create("/foo/foo/foo", "bar", Permanent, 1, 1)
-
 	// watch at a deeper path
 	c, _ := fs.WatcherHub.watch("/foo/foo/foo", false, 0)
-	fs.Delete("/foo", true, 2, 1)
-	e := <-c
-	if e.Key != "/foo" {
-		t.Fatal("watch for delete fails")
+	fs.Create("/foo/foo/foo", "bar", Permanent, 1, 1)
+	
+	e := nonblockingRetrive(c)
+	if e.Key != "/foo/foo/foo" {
+		t.Fatal("watch for Create node fails")
+	}
+	
+	c, _ = fs.WatcherHub.watch("/foo/foo/foo", false, 0)
+	fs.Update("/foo/foo/foo", "car", Permanent, 2, 1)
+	e = nonblockingRetrive(c)
+	if e.Key != "/foo/foo/foo" {
+		t.Fatal("watch for Update node fails")
 	}
 
-	fs.Create("/foo/foo/foo", "bar", Permanent, 3, 1)
+	c, _ = fs.WatcherHub.watch("/foo/foo/foo", false, 0)
+	fs.TestAndSet("/foo/foo/foo", "car", 0, "bar", Permanent, 3, 1)
+	e = nonblockingRetrive(c)
+	if e.Key != "/foo/foo/foo" {
+		t.Fatal("watch for TestAndSet node fails")
+	}
+
+	c, _ = fs.WatcherHub.watch("/foo/foo/foo", false, 0)
+	fs.Delete("/foo", true, 4, 1) //recursively delete
+	e = nonblockingRetrive(c)
+	if e.Key != "/foo" {
+		t.Fatal("watch for Delete node fails")
+	}
+
+		
 	// watch at a prefix
 	c, _ = fs.WatcherHub.watch("/foo", true, 0)
-	fs.Delete("/foo/foo/foo", false, 4, 1)
-	e = <-c
-	if e.Key != "/foo/foo/foo" {
-		t.Fatal("watch for delete fails")
+	fs.Create("/foo/foo/boo", "bar", Permanent, 5, 1)
+	e = nonblockingRetrive(c)
+	if e.Key != "/foo/foo/boo" {
+		t.Fatal("watch for Create subdirectory fails")
 	}
 
+	c, _ = fs.WatcherHub.watch("/foo", true, 0)
+	fs.Update("/foo/foo/boo", "foo", Permanent, 6, 1)
+	e = nonblockingRetrive(c)
+	if e.Key != "/foo/foo/boo" {
+		t.Fatal("watch for Update subdirectory fails")
+	}
+
+	c, _ = fs.WatcherHub.watch("/foo", true, 0)
+	fs.TestAndSet("/foo/foo/boo", "foo", 0, "bar", Permanent, 7, 1)
+	e = nonblockingRetrive(c)
+	if e.Key != "/foo/foo/boo" {
+		t.Fatal("watch for TestAndSet subdirectory fails")
+	}
+
+	c, _ = fs.WatcherHub.watch("/foo", true, 0)
+	fs.Delete("/foo/foo/boo", false, 8, 1)
+	e = nonblockingRetrive(c)
+	if e.Key != "/foo/foo/boo" {
+		t.Fatal("watch for Delete subdirectory fails")
+	}
+
+
 }
 
 func createAndGet(fs *FileSystem, path string, t *testing.T) {
@@ -271,3 +400,12 @@ func createAndGet(fs *FileSystem, path string, t *testing.T) {
 	}
 
 }
+
+func nonblockingRetrive(c <-chan *Event) *Event{
+	select {
+	case e := <-c:
+		return e
+	default:
+		return nil
+	}
+}
\ No newline at end of file
diff --git a/file_system/watcher_test.go b/file_system/watcher_test.go
index ea8eae787..f874163ba 100644
--- a/file_system/watcher_test.go
+++ b/file_system/watcher_test.go
@@ -4,7 +4,7 @@ import (
 	"testing"
 )
 
-func TestWatch(t *testing.T) {
+func TestWatcher(t *testing.T) {
 	wh := newWatchHub(100)
 	c, err := wh.watch("/foo", true, 0)