@Test
 public void testSetGetBattery() {
   assertEquals(battery, equipment.getBattery());
   Battery bat = new Battery();
   equipment.setBattery(bat);
   assertEquals(bat, equipment.getBattery());
 }
 @Before
 public void setUp() throws Exception {
   equipment = new Equipment();
   equipment.setCost(COST);
   equipment.setSize(SIZE);
   inverter = new Inverter();
   equipment.setInverter(inverter);
   panels = new ArrayList<Panel>();
   equipment.setPanels(panels);
   battery = new Battery();
   equipment.setBattery(battery);
   inverters = new ArrayList<Inverter>();
 }