Basic total generation, no discounts for now

tests.rb

@@ -16,7 +16,22 @@ class TestCheckout < Minitest::Test
   def test_that_allowed_items_are_added
     @checkout.add(:PI5)
     @checkout.add(:ZERO2W)
+    @checkout.add(:PICO2)
 
-    assert_equal [:PI5, :ZERO2W].sort, @checkout.items.sort
+    assert_equal [:PI5, :ZERO2W, :PICO2].sort, @checkout.items.sort
   end
-end
+
+  def test_that_total_is_the_sum_of_all_items # Not accounting for discounts at the moment
+    @checkout.add(:PI5)     # 60.00
+    @checkout.add(:ZERO2W)  # 15.00
+    @checkout.add(:PICO2)   #  4.00
+                            # -----
+                            # 79.00 total
+
+    assert_equal 79.00, @checkout.total
+  end
+
+  def test_that_an_empty_checkout_total_is_zero
+    assert_equal 0.00, @checkout.total
+  end
+end