private void prepareTestData() {

    car1 = newCar("Black", "0B6 6835", "Škoda", 200.0);
    car2 = newCar("Red", "7B4 0044", "BMW", 500.0);
    car3 = newCar("White", "8B5 0983", "Volkwagen", 300.0);

    customer1 = newCustomer("Vitalii", "Chepeliuk", "Komarov", "5-20-86", "AK 373979");
    customer2 = newCustomer("Juraj", "Kolchak", "Komarov", "5-34-86", "AK 372548");
    customer3 = newCustomer("Martin", "Jirman", "Lazhot", "5-25-87", "AK 251245");

    carManager.addCar(car1);
    carManager.addCar(car2);
    carManager.addCar(car3);

    customerManager.addCustomer(customer1);
    customerManager.addCustomer(customer2);
    customerManager.addCustomer(customer3);

    carWithoutID = newCar("Green", "8B3 9763", "Audi", 400.0);
    carNotInDB = newCar("Blue", "3B6 8463", "Peugeot", 0.0);
    carNotInDB.setID(car3.getID() + 100);

    customerWithoutID = newCustomer("Martin", "Pulec", "Brno", "5-11-24", "AK 897589");
    customerNotInDB = newCustomer("Lukas", "Rucka", "Brno", "5-21-06", "AK 256354");
    customerNotInDB.setID(customer3.getID() + 100);
    customerNotInDB.setActive(true);
  }
 @Before
 public void setUp() throws SQLException {
   dataSource = prepareDataSource();
   DBUtils.createTables(dataSource);
   manager = new RentManagerImplementation();
   manager.setDataSource(dataSource);
   carManager = new CarManagerImplementation();
   carManager.setDataSource(dataSource);
   customerManager = new CustomerManagerImplementation();
   customerManager.setDataSource(dataSource);
   prepareTestData();
 }