PHP 7:
This is usually bundled with your operating system, or fetchable using a package manager like apt or homebrew.
Windows users can find the latest version here: https://windows.php.net/download#php-7.3
If you want to compile from source code, that can be found here: https://www.php.net/downloads.php
Composer:
Composer is PHP's main package and dependency management tool.
It can be downloaded here: https://getcomposer.org/download/
To begin the kata, install the dependencies and run phpunit:
cd php7
composer install
vendor/bin/phpunit
If the "install" command does not work, try running composer update instead.
This will tell composer that it has permission to look for a newer version of
its dependencies.
If things are still not cooperating, you can try this extreme approach:
composer remove phpunit/phpunit
composer require phpunit/phpunit
To exercise the code outside of phpunit, for example to visually confirm that it is working,
use the texttest_fixture script:
php fixtures/texttest_fixture.php
PHPUnit has a very thorough reference manual. It would be particularly useful to explore the Data Providers section.