skorolchuk / go-checkout-kata

Checkout Kata Solution in Go

Overview

Implement the code for a checkout system that handles pricing schemes such as "pineapples cost 50, three pineapples cost 130."

Implement the code for a supermarket checkout that calculates the total price of a number of items.

In a normal supermarket, things are identified using Stock Keeping Units, or SKUs. In our store, we’ll use individual letters of the alphabet (A, B, C, and so on). Our goods are priced individually.

In addition, some items are multi-priced: buy n of them, and they’ll cost you y. For example, item A might cost 50 individually, but this week we have a special offer: buy three As and they’ll cost you 130.

In fact the prices are:

SKU	Unit Price	Special Price
A	50	3 for 130
B	30	2 for 45
C	20
D	15

The checkout accepts items in any order, so that if we scan a B, an A, and another B, we’ll recognize the two Bs and price them at 45 (for a total price so far of 95).

The pricing changes frequently, so pricing should be independent of the checkout.pricing changes frequently, so pricing should be independent of the checkout. The interface to the checkout could look like:

interface ICheckout
{
    void Scan(string item);
    int GetTotalPrice();
}

Structure

Folder	Description
cmd/checkout-cli	Sample CLI implementation of Checkout process
internal/pkg/checkout	Folder contains package with solution of Checkout API
internal/pkg/history	Folder contains API for managing scan history
internal/pkg/sku	Folder contains SKU catalog models and methods
test	SKU catalog samples which used in unit tests and CLI default configuration
bin (after make build)	Location for executable checkout-cli binary file

Commands

Command	Description
make fmt	Command will re-format Go files
make vet	Command will lint Go files
make clean	Command will clean Go package cache and bin folder
make build	Command will clean up, format and lint code and then build checkout-cli binary
make run	Command will run checkout-cli application
make tests	Command will run all unit tests
make lint	Command will run staticcheck tool
make tidy	Command will sync Go modules
make deps-cleancache	Command will clean up Go modules cache
make list	Command will list Go modules

How To

Prerequisites

Install go 1.16+ and GNU make

Hot to run

~ make run-example

~ make build
~ ./bin/checkout-cli --scan-series AABCDBBA

NOTE: --scan-series argument accepts series of SKU names presented in SKU catalog file