Caches - Normalize dependency on php-cache integration-tests

[totten]

Overview

CiviCRM includes cache drivers that comply with PSR-16. The php-cache integration-tests provide a base-class for testing these drivers to ensure compliance with PSR-16.

The base-class was originally loaded as an impromptu fork which provided support for PHPUnit 4. However, since Civi's test suite no longer supports PHPUnit 4 (and does support PHPUnit 6), we can switch to the normal/non-forked version of the base-class.

Before

• civicrm-packages provides a patched/forked copy of SimpleCacheTest named LegacySimpleCacheTest.
• The Civi tests extend a variant that worked in PHPUnit 4+5 (class E2E_Cache_CacheTestCase extends ... LegacySimpleCacheTest ... extends \PHPUnit_Framework_TestCase).

After

• composer.json provides the canonical SimpleCacheTest.
• The Civi tests extend a variant that works in PHPUnit 5+6 (class E2E_Cache_CacheTestCase extends ... SimpleCacheTest ... extends \PHPUnit\Framework\TestCase).
• The folder civicrm-packages.git/Cache can be deleted.

[civibot]

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