diff --git a/bisect.go b/bisect.go
index b4f929a..2bcef3a 100644
--- a/bisect.go
+++ b/bisect.go
@@ -2,9 +2,6 @@ package prompt
 
 import "sort"
 
-// Thanks!! https://play.golang.org/p/y9NRj_XVIW
-// TODO: Add unit tests
-
 // BisectLeft to Locate the insertion point for v in a to maintain sorted order.
 func BisectLeft(a []int, v int) int {
 	return bisectLeftRange(a, v, 0, len(a))
diff --git a/bisect_test.go b/bisect_test.go
new file mode 100644
index 0000000..0baed7c
--- /dev/null
+++ b/bisect_test.go
@@ -0,0 +1,21 @@
+package prompt
+
+import (
+	"testing"
+)
+
+// Thanks!! https://play.golang.org/p/y9NRj_XVIW
+
+func TestBisectRight(t *testing.T) {
+	in := []int{1, 2, 3, 3, 3, 6, 7}
+
+	r := BisectRight(in, 0)
+	if r != 0 {
+		t.Error("number 0 should inserted at 0 position, but got %d", r)
+	}
+
+	r = BisectRight(in, 4)
+	if r != 5 {
+		t.Error("number 4 should inserted at 5 position, but got %d", r)
+	}
+}