Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in /var/www/html/composer/vendor/paragonie/constant_time_encoding/tests/Base64DotSlashTest.php:10 Stack trace: #0 {main} thrown in /var/www/html/composer/vendor/paragonie/constant_time_encoding/tests/Base64DotSlashTest.php on line 10