diff --git a/g/os/gcron/gcron_z_example_1_test.go b/g/os/gcron/gcron_z_example_1_test.go
new file mode 100644
index 000000000..4f5b6db13
--- /dev/null
+++ b/g/os/gcron/gcron_z_example_1_test.go
@@ -0,0 +1,22 @@
+// Copyright 2019 gf Author(https://gitee.com/johng/gf). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://gitee.com/johng/gf.
+
+
+package gcron_test
+
+import (
+    "gitee.com/johng/gf/g/os/gcron"
+    "gitee.com/johng/gf/g/os/glog"
+    "time"
+)
+
+func ExampleCron_AddSingleton() {
+    gcron.AddSingleton("* * * * * *", func() {
+        glog.Println("doing")
+        time.Sleep(2*time.Second)
+    })
+    select { }
+}
diff --git a/geg/other/test2.go b/geg/other/test2.go
index 51cba4c94..65b39b5ea 100644
--- a/geg/other/test2.go
+++ b/geg/other/test2.go
@@ -1,12 +1,15 @@
 package main
 
 import (
-    "fmt"
-    "gitee.com/johng/gf/g/util/grand"
+    "gitee.com/johng/gf/g/os/gcron"
+    "gitee.com/johng/gf/g/os/glog"
+    "time"
 )
 
 func main() {
-    fmt.Println(float64(10)/3)
-    fmt.Println(grand.Meet(1, 1))
-    fmt.Println(grand.MeetProb(float64(1)/2))
+    gcron.AddSingleton("* * * * * *", func() {
+        glog.Println("doing")
+        time.Sleep(2*time.Second)
+    })
+    select { }
 }
\ No newline at end of file