public void Items_MaxDays_check()
{
AdultBook a = new AdultBook();
ChildBook c = new ChildBook();
DVD d = new DVD();
VHS v = new VHS();
Assert.AreEqual(14, a.maxDays());
Assert.AreEqual(7, c.maxDays());
Assert.AreEqual(2, d.maxDays());
Assert.AreEqual(3, v.maxDays());
}