@Test
  public void shouldReturnSumOfTotalTaxAndPriceForGoodsPurchased() {
    ShoppingBasket basket = new ShoppingBasket();

    Good good1 = new Good("rice", 12.49, new Type("book"));
    Good good2 = new Good("wheat", 14.99, new Type("cd"));
    Good good3 = new Good("choco", 0.85, new Type("food"));

    basket.addToIt(good1, 1);
    basket.addToIt(good2, 1);
    basket.addToIt(good3, 1);
    basket.purchase();

    assertEquals(new Receipt(basket).total(), 29.83, 0.1);
  }
  @Test
  public void shouldReturnSumOfGoodsPricesPurchased() {
    ShoppingBasket basket = new ShoppingBasket();

    Good good1 = new Good("rice", 34.90, new Type("food"));
    Good good2 = new Good("wheat", 34.90, new Type("food"));

    basket.addToIt(good1, 1);
    basket.addToIt(good2, 2);

    assertEquals(new Receipt(basket).sumOfItemPrices(), 34.90 * 3, 0.01);
  }