Reimplement checkout item removal. All existing tests now pass

test/checkout_test.rb

@@ -127,72 +127,54 @@ class CheckoutTest < Minitest::Test
   # Item removal
 
   def test_that_removing_an_item_not_in_the_checkout_removes_nothing
-    skip
+    @checkout.add(product_id: 'PICO2')
+    @checkout.remove(product_id: 'PI5')
 
-    @checkout.add(:PICO2)
-    @checkout.remove(:PI5)
-
-    assert_equal [:PICO2], @checkout.items
+    assert_equal({ 'PICO2' => 1 }, @checkout.item_quantities)
   end
 
   def test_that_items_are_removed_one_by_one
-    skip
+    @checkout.add(product_id: 'ZERO2W', quantity: 4)
+    @checkout.add(product_id: 'PICO2', quantity: 3)
 
-    4.times do
-      @checkout.add(:ZERO2W)
-    end
+    assert_equal({ 'ZERO2W' => 4, 'PICO2' => 3 }.sort, @checkout.item_quantities.sort)
 
-    3.times do
-      @checkout.add(:PICO2)
-    end
+    @checkout.remove(product_id: 'ZERO2W')
 
-    assert_equal [:ZERO2W, :ZERO2W, :ZERO2W, :ZERO2W, :PICO2, :PICO2, :PICO2].sort, @checkout.items.sort
+    assert_equal({ 'ZERO2W' => 3, 'PICO2' => 3 }.sort, @checkout.item_quantities.sort)
 
-    @checkout.remove(:ZERO2W)
+    @checkout.remove(product_id: 'PICO2')
 
-    assert_equal [:ZERO2W, :ZERO2W, :ZERO2W, :PICO2, :PICO2, :PICO2].sort, @checkout.items.sort
+    assert_equal({ 'ZERO2W' => 3, 'PICO2' => 2 }.sort, @checkout.item_quantities.sort)
 
-    @checkout.remove(:PICO2)
 
-    assert_equal [:ZERO2W, :ZERO2W, :ZERO2W, :PICO2, :PICO2].sort, @checkout.items.sort
+    @checkout.remove(product_id: 'PICO2', quantity: 2)
 
-    2.times do
-      @checkout.remove(:PICO2)
-    end
-
-    assert_equal [:ZERO2W, :ZERO2W, :ZERO2W].sort, @checkout.items.sort
+    assert_equal({ 'ZERO2W' => 3 }.sort, @checkout.item_quantities.sort)
   end
 
   def test_that_total_is_correctly_recalculated_when_items_are_added
-    skip
 
-    2.times do
-      @checkout.add(:PICO2)
-    end
+    @checkout.add(product_id: 'PICO2', quantity: 2)
 
     assert_equal 8.00, @checkout.total
 
-    @checkout.add(:PICO2) # 3 in total now, so discount applies
+    @checkout.add(product_id: 'PICO2', quantity: 1) # 3 in total now, so discount applies
 
     assert_equal 10.50, @checkout.total
 
-    4.times do
-      @checkout.add(:ZERO2W) # 30.00 with BOGOF
-    end
+    @checkout.add(product_id: 'ZERO2W', quantity: 4)
 
     assert_equal 40.50, @checkout.total
   end
 
   def test_that_total_is_correctly_recalculated_when_items_are_removed
-    skip
 
-    3.times do
-      @checkout.add(:PICO2) # Bulk discount applies
-    end
+    @checkout.add(product_id: 'PICO2', quantity: 3)
 
     assert_equal 10.50, @checkout.total
 
-    @checkout.remove(:PICO2) # Bulk discount no longer applies
+    @checkout.remove(product_id: 'PICO2', quantity: 1) # Bulk discount no longer applies
 
     assert_equal 8.00, @checkout.total
   end