@Test
   public void testCharge() {
      System.out.println("Test charge()");
      floorType newFloorType = floorType.HIGH_PILE_CARPET;
      BatteryAndDirtBin instance = new BatteryAndDirtBin(newFloorType);
      instance.swept();
      instance.swept();
      instance.swept();
      instance.swept();
      assertEquals(instance.charge(), 380);
      for (int i = 0; i < 50; i++) {
         instance.swept();
      }
      assertEquals(instance.charge(), 0);
   }