diff --git a/go.mod b/go.mod
index 58688d3..f7ec693 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,5 @@
 module github.com/robotn/gohook
 
 go 1.13
+
+require github.com/vcaesar/tt v0.0.0-20200219144246-a190abe69d64
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..74d89ab
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+github.com/vcaesar/tt v0.0.0-20200219144246-a190abe69d64 h1:MwxT8hyvPcPafJ2LDmoFuH7Xpz5LZ6W3dKzwVQAHD/k=
+github.com/vcaesar/tt v0.0.0-20200219144246-a190abe69d64/go.mod h1:GHPxQYhn+7OgKakRusH7KJ0M5MhywoeLb8Fcffs/Gtg=
diff --git a/hook_test.go b/hook_test.go
new file mode 100644
index 0000000..30d87e7
--- /dev/null
+++ b/hook_test.go
@@ -0,0 +1,15 @@
+package hook
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/vcaesar/tt"
+)
+
+func TestAdd(t *testing.T) {
+	fmt.Println("hook test...")
+
+	e := Start()
+	tt.NotNil(t, e)
+}