diff --git a/base64_arm64_test.go b/base64_arm64_test.go
index 8bf7494..2140daa 100644
--- a/base64_arm64_test.go
+++ b/base64_arm64_test.go
@@ -60,7 +60,7 @@ func TestUrlEncodeSIMD(t *testing.T) {
 		expected := []byte(p.encoded)
 		dst := make([]byte, len(expected))
 
-		ret := encodeAsm(dst, src, &StdEncoding.encode)
+		ret := encodeAsm(dst, src, &URLEncoding.encode)
 		if ret != len(expected) {
 			t.Fatalf("should return %v", len(expected))
 		}