diff --git a/time/time.go b/time/time.go
index c369d48..bc5b805 100644
--- a/time/time.go
+++ b/time/time.go
@@ -67,6 +67,10 @@ func (t Time) UnixMilli() int64 {
 	return t.Time().UnixNano() / int64(Millisecond)
 }
 
+func (t Time) Add(d Duration) Time {
+	return New(t.Time().Add(d))
+}
+
 func (t Time) String() string {
 	return t.Time().Format(ISO8601Milli)
 }
diff --git a/time/time_test.go b/time/time_test.go
index e98eac6..f0c9293 100644
--- a/time/time_test.go
+++ b/time/time_test.go
@@ -8,7 +8,7 @@ import (
 )
 
 func TestJSON(t *testing.T) {
-	before := New(2008, M8, 8, 20, 8, 8, 8*1000*1000)
+	before := Date(2008, M8, 8, 20, 8, 8, 8*1000*1000)
 	str := json.MustMarshalToString(before)
 	after := Time{}