@Test
 public void testSetPluge2() {
   Walkman_2 walkman = new Walkman_2();
   assertFalse(walkman.terminal2.isJack());
   walkman.setPluge2();
   assertTrue(walkman.terminal2.isJack());
 }
 @Test
 public void testListenTape() {
   // �ڂŊm�F���܂�
   Walkman_2 walkman = new Walkman_2();
   walkman.listenTape();
   walkman.setTape();
   walkman.listenTape();
   walkman.setPluge();
   walkman.listenTape();
   walkman.setPluge2();
   walkman.listenTape();
 }