Sales Taxes (Kata)

This is a Kata on the sales taxes problem.

The main issue of the problem is to calculate the selling price of various products, including the Basic Sales Tax and the Import Duty when applicable.
The ultimate goal is to write an application that prints out the receipt details for three predefined shopping baskets.

You can find more details about the problem and the solution respectively in the PROBLEM.md and SOLUTION.md files.

Technical Information

This Kata was written in PHP Language.
The source code was fixed using PHP CS Fixer and checked by static analysis tools such as Psalm and PHPStan, and also includes a test suite in PHPUnit.

The application run inside an environment based on 🐳 Docker (docker containers built used docker-compose).

Quick start

Install all dependencies and start the application server:

make install

The installation could be fails due conflicts with the ports used by the application and by your host.
In this case you can solve by changing such ports in the .env file (see Customizations).

For further details about the make commands:

make help

The application will be available opening the browser at this URL address:

• http://localhost

Now, you can enter inside the app docker container shell to interact from command line:

make shell

In alternative, if you use Visual Studio Code, you can work directly inside the docker container:

• press F1: "> Remote-Containers: Reopen in Container"

(For further details see .devcontainer/devcontainer.json file)

From the docker container shell, you can execute other commands.

Run the application from the the terminal:

php public/index.php

Fix the source code:

./tools/php-cs-fixer/vendor/bin/php-cs-fixer fix src

Check the source code with static analysis with Psalm and PHPStan:

./vendor/bin/psalm --show-info=true
./vendor/bin/phpstan analyse src tests --memory-limit 256M

Test the application with PHPUnit:

./vendor/bin/phpunit --testdox

How To

Customizations

You can customize the configuration of the docker containers changing the variables in the .env file.

Key	Description	Current value
APP_NAME	Application name	sales-taxes
NGINX_VERSION	NGINX version	1.19
NGINX_HOST	NGINX server_name	localhost
NGINX_ROOT	NGINX root	/var/www
NGINX_PORT_HTTP	NGINX http port	80
NGINX_PORT_HTTPS	NGINX https port	443
PHP_VERSION	PHP version	8
PHP_SYSTEM_TZ	PHP timezone	Europe/Rome
PHP_PORT	PHP port	9000
XDEBUG_MODE	Xdebug mode	off
XDEBUG_CLIENT_PORT	Xdebug client port	9003
XDEBUG_CLIENT_HOST	Xdebug client host	localhost

Initial Setup

Installations

Install PHP CS Fixer:

mkdir --parents tools/php-cs-fixer
composer require --working-dir=tools/php-cs-fixer friendsofphp/php-cs-fixer

Install Psalm:

composer require --dev vimeo/psalm

Install PHPStan:

composer require --dev phpstan/phpstan

Install PHPUnit:

composer require --dev phpunit/phpunit

Configurations

Config Psalm adding the psalm.xml file (or executing ./vendor/bin/psalm --init):

<?xml version="1.0"?>
<psalm
    errorLevel="3"
    resolveFromConfigFile="true"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="https://getpsalm.org/schema/config"
    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
>
    <projectFiles>
        <directory name="public" />
        <directory name="src" />
        <ignoreFiles>
            <file name="public/autoload.php" />
            <directory name="tests" />
            <directory name="vendor" />
        </ignoreFiles>
    </projectFiles>
</psalm>

Config PHPStan adding the phpstan.neon file:

parameters:
    level: 6
    paths:
        - public
        - src
        - tests

Config PHPUnit adding the phpunit.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<phpunit
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/phpunit.xsd"
        colors="true"
        stopOnError="false"
        stopOnFailure="false"
        stopOnIncomplete="false"
        stopOnSkipped="false"
        stopOnRisky="true"
        verbose="true">
  <testsuites>
    <testsuite name="ValueObject">
      <file>tests/ValueObject/CategoryTest.php</file>
    </testsuite>
    <testsuite name="Entity">
      <file>tests/Entity/ProductTest.php</file>
      <file>tests/Entity/ShoppingItemTest.php</file>
      <file>tests/Entity/ShoppingBasketTest.php</file>
      <file>tests/Entity/SalesItemTest.php</file>
      <file>tests/Entity/SalesReceiptTest.php</file>
    </testsuite>
    <testsuite name="Service">
      <file>tests/Service/RoundingUp005Test.php</file>
    </testsuite>
    <testsuite name="Application">
      <file>tests/ApplicationTest.php</file>
    </testsuite>
  </testsuites>
</phpunit>