if expecting := []byte("________"); n != 0 || !bytes.Equal(s, expecting) {
			t.Errorf("got n = %d, s = %s, expecting n = 0, s = %s", n, s, expecting)
		}

		n = Copy(val, ValueOf("hello"))
		if expecting := []byte("hello___"); n != 5 || !bytes.Equal(s, expecting) {
			t.Errorf("got n = %d, s = %s, expecting n = 5, s = %s", n, s, expecting)
		}

		n = Copy(val, ValueOf("helloworld"))