clean up calculate_best method. Check that an optimal match is being …

…returned

lib/order_line.rb

@@ -26,39 +26,28 @@ def optimal(product)
     calculate_best(same_packs, diff_packs)
   end
 
-  def calculate_best(exact, partial)
-    # If there are no matches on same_packs, return diff_packs
-    unless exact.any?
-      puts "\nThis is it #{partial.inspect}"
-      return partial
-    end
+  # Calculate best method
+  # @param same_packs [Enumerator]
+  # @param diff_packs [Enumerator]
+  # @return optimum combo of packs [Enumerator]
+  def calculate_best(same_packs, diff_packs)
+    return diff_packs unless same_packs.any?
 
-    # If there are no matches on diff_packs, return same_packs
-    unless partial.any?
-      puts "\nThis is it #{exact.inspect}"
-      return exact
-    end
+    return same_packs unless diff_packs.any?
 
-    # If there's one of each, work out which is the better price
+    # Get the total price of diff_packs
     sub_total = []
-    partial.each do |_x, _y, _z, val|
-      sub_total << val
-    end
+    diff_packs.each { |_x, _y, _z, val| sub_total << val }
 
-    # # Find total cost of sub_items for a partial match
     line_total = sub_total.inject(:+)
 
     # Return the cheapest option
-    if [exact.min[3], line_total].min == line_total
-      puts "\nThis is it #{partial.inspect}"
-      return partial
-    end
+    return diff_packs if [same_packs.min[3], line_total].min == line_total
 
-    exact
+    same_packs
   end
 
   def present_line(packs)
-    puts "PACKS: #{packs}"
     sub_total = []
     sub_item = []
     packs.each do |k, v, i|
@@ -119,7 +108,7 @@ def diff_match(pack_qtys, matches, part_order)
     matches.each do |x, y, z|
       val = order_qty - (x * y)
       pack_qtys.detect do |a|
-        # TODO: This can be optimised. a.include?(val) does not cooperate with Money
+        # TODO: Optimised. a.include?(val) does not cooperate with Money
         if a[0] == val || a[0] == val || a[0] * 3 == val
           part_order << [x, y, z]
           part_order << [val / a[0], a[0], a[1]]

lib/shop.rb

@@ -36,12 +36,12 @@ def choose_items(input)
   end
 
   def exec(order_line)
-    order.add_item(
-      order_line,
-      order_line.present_line(
-        order_line.optimal(order_line.order_item.name)
-      )
-    )
+    optimal = order_line.optimal(order_line.order_item.name)
+
+    return unless optimal.any?
+
+    order.add_item(order_line,
+                   order_line.present_line(optimal))
 
     order_line
   end

spec/order_line_spec.rb

@@ -32,6 +32,66 @@
     end
   end
 
+  describe '#calculate_best' do
+    it 'should return optimum combination of packs which is an Enumerator' do
+      order_item = Item.new('rockmelons')
+      instance = OrderLine.new(13, order_item)
+
+      pack_qtys = []
+      order_item.packs(instance.order_item.name).each { |p| pack_qtys << [p.qty, p.price] }
+
+      same_packs = instance.send(:price_check, instance.send(:same_match, pack_qtys, []), [])
+      diff_packs = instance.send(:price_check, instance.send(:diff_match, pack_qtys, [], []), [])
+
+      expect(instance.calculate_best(same_packs, diff_packs)).to be_a Enumerator
+    end
+  end
+
+  describe '#calculate_best' do
+    it 'should return optimum combination of packs which is an Enumerator' do
+      order_item = Item.new('watermelons')
+      instance = OrderLine.new(10, order_item)
+
+      pack_qtys = []
+      order_item.packs(instance.order_item.name).each { |p| pack_qtys << [p.qty, p.price] }
+
+      same_packs = instance.send(:price_check, instance.send(:same_match, pack_qtys, []), [])
+      diff_packs = instance.send(:price_check, instance.send(:diff_match, pack_qtys, [], []), [])
+
+      expect(instance.calculate_best(same_packs, diff_packs)).to be_a Enumerator
+    end
+  end
+
+  describe '#calculate_best' do
+    it 'should return optimum combination of packs which is an Enumerator' do
+      order_item = Item.new('pineapples')
+      instance = OrderLine.new(14, order_item)
+
+      pack_qtys = []
+      order_item.packs(instance.order_item.name).each { |p| pack_qtys << [p.qty, p.price] }
+
+      same_packs = instance.send(:price_check, instance.send(:same_match, pack_qtys, []), [])
+      diff_packs = instance.send(:price_check, instance.send(:diff_match, pack_qtys, [], []), [])
+
+      expect(instance.calculate_best(same_packs, diff_packs)).to be_a Enumerator
+    end
+  end
+
+  describe '#calculate_best' do
+    it 'should return an Enumerator which is empty if the quantity cannot be made up of packs' do
+      order_item = Item.new('pineapples')
+      instance = OrderLine.new(1, order_item)
+
+      pack_qtys = []
+      order_item.packs(instance.order_item.name).each { |p| pack_qtys << [p.qty, p.price] }
+
+      same_packs = instance.send(:price_check, instance.send(:same_match, pack_qtys, []), [])
+      diff_packs = instance.send(:price_check, instance.send(:diff_match, pack_qtys, [], []), [])
+
+      expect(instance.calculate_best(same_packs, diff_packs)).to be_a Enumerator
+    end
+  end
+
   describe '#present_line' do
     it 'should return whole_packs which is an Array' do
       instance = OrderLine.new(12, Item.new('watermelons'))

spec/shop_spec.rb

@@ -48,5 +48,11 @@
 
       expect(instance.send(:exec, OrderLine.new(10, Item.new('watermelons')))).to be_a OrderLine
     end
+
+    it 'should return nil if an optimal order cannot be made up of packs' do
+      instance = Shop.new(Order.new)
+
+      expect(instance.send(:exec, OrderLine.new(1, Item.new('watermelons')))).to be_nil
+    end
   end
 end