dianamajek7 / checkoutkata Goto Github PK

Checkout Kata

In a normal supermarket, items are identified by ‘stock keeping units’ or ‘SKUs’. In our store, we will use individual letters of the alphabet, A, B, C etc, as the SKUs. Our goods are priced individually. In addition, some items are multipriced: buy n of them and which will cost you y. For example, item A might cost 50 pence individually but this week we have a special offer where you can buy 3 As for £1.30.

• Item A | Unit Price: 50 | Special Price: 3 for 130
• Item B | Unit Price: 30 | Special Price: 2 for 45
• Item C | Unit Price: 20
• Item D | Unit Price: 15

Our checkout accepts items in any order so if we scan a B, then an A, then another B, we will recognise the two B’s and price them at 45 (for a total price so far of 95).

Extra points: Because the pricing changes frequently we will need to be able to pass in a set of pricing rules each time we start handling a checkout transaction.

• The Design Pattern used in this application followed a TDD Approach with the use of Object-Oriented design principles known as SOLID
  • within Solid patterns This application makes use of Single Responsibility Principle which gives the quality assurance that the Open-Close Principle is also met
  • The application also enforce the use of loose coupling and high cohesion
  • The application also enforces encapsulation, Overloading, and Composition through a HAS-A relationships between entities
    • i.e (between Product : StockItems) One to Many Relationship
  • Enforces the use Functional Programming and Lambda Functions
  • With the use OOP approach opens flexibility for reusable code and possible future migrations
  • i.e(making use of constants to make it easier for future change to a final variable in one location)
  • The logic, presentation entities and views are well separated and managed

• This is a standalone console application with no com.challenge.checkoutKata.UI
• The com.challenge.checkoutKata.UI Class is the runner class which contains static main function
• Extensive use of assertions within Unit test, ensures to test the classes and its methods
  • the CheckoutTest Class handles the different edge cases
• Classes like Checkout and Basket class consists of operations which occurs in a real world
  • i.e: a shopping cart with a list of items and the no of occurrence including returning the total price of each item occurrence in the basket.
• To run the application - "UI.Java" is the main file and I have also added a jar file including the unit tests.
  • Application Framework uses Maven and Java 8 with no third-Party libraries or dependencies, it should be straightforward to spin up on a local machine
    • "mvn clean install" to build the project as well as run the test
    • "mvn test" to run just the test

• To keep track of operations made between menu option 2 and menu option, it stores the wholesale and inventory list in a file located under resources
  • Unit tests also has its files for both the Inventory and wholesale list
• There are three menu options on the initial run of the application:
  • To do shopping by adding items into the cart and a receipt is generated
    • validator - ensures to validate input with an existing Sku/itemName
  • To add or remove a stock item, once operation is completed it is updated in the file, making it reusable - It also avoids duplicate item name (SKUs) to be added in the inventory list
  • To add or remove a Special Pricing rule for an item, once operation is completed it is updated in the file, making it reusable
    • It avoids duplicating Pricing rule with same itemName and no of item on offer