diff --git a/observer/observer.go b/observer/observer.go
index 8b556ad..33c7d8c 100644
--- a/observer/observer.go
+++ b/observer/observer.go
@@ -41,10 +41,14 @@ func (o *observer) Remove(id string, rch chan interface{}) error {
 			newArr = append(newArr, ch)
 		} else {
 			close(ch)
+			ch = nil
 		}
 	}
-
-	o.events[id] = newArr
+	if len(newArr) == 0 {
+		delete(o.events,id)
+	} else {
+		o.events[id] = newArr
+	}
 	return nil
 }
 func (o *observer) Notify(id string, arg interface{}) error {
@@ -73,6 +77,9 @@ func init() {
 	})
 }
 
+
+// interface
+
 func Add(id string, ch chan interface{}) error {
 	return _observer.Add(id, ch)
 }
@@ -82,3 +89,7 @@ func Remove(id string, rch chan interface{}) error {
 func Notify(id string, arg interface{}) error {
 	return _observer.Notify(id, arg)
 }
+
+func GetCount() (int) {
+	return len(_observer.events)
+}
diff --git a/observer/observer_test.go b/observer/observer_test.go
index aecca24..4fdb4da 100644
--- a/observer/observer_test.go
+++ b/observer/observer_test.go
@@ -1,7 +1,97 @@
 package observer
 
-import "testing"
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+	"time"
+)
 
-func TestObserver(t *testing.T) {
+type Test struct {
+	Id string
+}
 
-}
\ No newline at end of file
+func TestAddNotifyObserver(t *testing.T) {
+
+	// others package notify call
+	go func() {
+		time.Sleep(1 * time.Second)
+		Notify("test", Test{Id: "test"})
+	}()
+
+	ch := make(chan interface{},0)
+	Add("test", ch)
+
+	dd := <-ch
+	bb := dd.(Test)
+	assert.Equal(t, "test", bb.Id)
+}
+
+func TestRemoveObserver(t *testing.T) {
+
+	ch := make(chan interface{},0)
+	Add("test", ch)
+
+	err := Remove("test", ch)
+	assert.Equal(t, nil, err)
+}
+
+// +build ignore
+func TestMultiAddObserver(t *testing.T) {
+	ch1 := make(chan interface{},0)
+	ch2 := make(chan interface{},0)
+	ch3 := make(chan interface{},0)
+	ch4 := make(chan interface{},0)
+	ch5 := make(chan interface{},0)
+	
+	go func() {
+		d:=<-ch1
+		dd := d.(Test)
+		assert.Equal(t, dd.Id,"test")
+	}()
+	
+	go func() {
+		d:=<-ch2
+		dd := d.(Test)
+		assert.Equal(t, dd.Id,"test")
+	}()
+	
+	go func() {
+		d:=<-ch3
+		dd := d.(Test)
+		assert.Equal(t, dd.Id,"test")
+	}()
+	
+	go func() {
+		d:=<-ch4
+		dd := d.(Test)
+		assert.Equal(t, dd.Id,"test")
+	}()
+	
+	go func() {
+		d:=<-ch4
+		dd := d.(Test)
+		assert.Equal(t, dd.Id,"test")
+	}()
+	
+	Add("test", ch1)
+	Add("test", ch2)
+	Add("test", ch3)
+	Add("test", ch4)
+	Add("test", ch5)
+	
+	// others package notify call
+	go func() {
+		time.Sleep(1 * time.Second)
+		Notify("test", Test{Id: "test"})
+
+		time.Sleep(2 * time.Second)
+		Remove("test", ch1)
+		Remove("test", ch2)
+		Remove("test", ch3)
+		Remove("test", ch4)
+		Remove("test", ch5)
+	}()
+	
+	time.Sleep(1 * time.Second)
+	
+}