diff --git a/utils_test.go b/utils_test.go
new file mode 100644
index 0000000..1a156df
--- /dev/null
+++ b/utils_test.go
@@ -0,0 +1,16 @@
+package godzilla
+
+import "fmt"
+
+func ExampleGetString() {
+	b := []byte("ABC")
+	str := GetString(b)
+	fmt.Println(str)
+	fmt.Println(len(b) == len(str))
+
+	b = nil
+	str = GetString(b)
+	fmt.Println(str)
+	fmt.Println(len(b) == len(str))
+	fmt.Println(len(str))
+}