diff -up ./phpunit.rpm ./phpunit
--- ./phpunit.rpm	2021-06-07 07:13:03.000000000 +0200
+++ ./phpunit	2021-06-07 07:13:10.372992677 +0200
@@ -27,25 +27,12 @@ if (!ini_get('date.timezone')) {
     ini_set('date.timezone', 'UTC');
 }
 
-foreach (array(__DIR__ . '/../../autoload.php', __DIR__ . '/../vendor/autoload.php', __DIR__ . '/vendor/autoload.php') as $file) {
-    if (file_exists($file)) {
-        define('PHPUNIT_COMPOSER_INSTALL', $file);
-
-        break;
-    }
-}
-
-unset($file);
-
-if (!defined('PHPUNIT_COMPOSER_INSTALL')) {
-    fwrite(
-        STDERR,
-        'You need to set up the project dependencies using Composer:' . PHP_EOL . PHP_EOL .
-        '    composer install' . PHP_EOL . PHP_EOL .
-        'You can learn all about Composer on https://getcomposer.org/.' . PHP_EOL
-    );
-
-    die(1);
+// Libraries PATH
+if (file_exists('./vendor/phpunit/phpunit/phpunit') && file_exists('./vendor/autoload.php')) {
+    echo "\n==== Redirecting to composer installed version in vendor/phpunit ====\n\n";
+    define ('PHPUNIT_COMPOSER_INSTALL', realpath('./vendor/autoload.php'));
+} else {
+    define ('PHPUNIT_COMPOSER_INSTALL', '/usr/share/php/PHPUnit8/autoload.php');
 }
 
 $options = getopt('', array('prepend:'));
@@ -58,4 +45,8 @@ unset($options);
 
 require PHPUNIT_COMPOSER_INSTALL;
 
-PHPUnit\TextUI\Command::main();
+if (class_exists('PHPUnit_TextUI_Command')) {
+    PHPUnit_TextUI_Command::main(); // PHPUnit v5 or older
+} else {
+    PHPUnit\TextUI\Command::main(); // PHPUnit v6 or newer
+}
diff -up ./src/Util/Configuration.php.rpm ./src/Util/Configuration.php
--- ./src/Util/Configuration.php.rpm	2021-06-07 07:13:03.000000000 +0200
+++ ./src/Util/Configuration.php	2021-06-07 07:13:10.372992677 +0200
@@ -929,7 +929,7 @@ final class Configuration
     private function validateConfigurationAgainstSchema(): void
     {
         $original    = libxml_use_internal_errors(true);
-        $xsdFilename = __DIR__ . '/../../phpunit.xsd';
+        $xsdFilename = __DIR__ . '/../phpunit.xsd';
 
         if (defined('__PHPUNIT_PHAR_ROOT__')) {
             $xsdFilename = __PHPUNIT_PHAR_ROOT__ . '/phpunit.xsd';
diff -up ./tests/bootstrap.php.rpm ./tests/bootstrap.php
--- ./tests/bootstrap.php.rpm	2021-06-07 07:13:10.372992677 +0200
+++ ./tests/bootstrap.php	2021-06-07 07:15:29.571502817 +0200
@@ -8,7 +8,7 @@
  * file that was distributed with this source code.
  */
 if (!defined('PHPUNIT_COMPOSER_INSTALL')) {
-    define('PHPUNIT_COMPOSER_INSTALL', dirname(__DIR__) . '/vendor/autoload.php');
+    define('PHPUNIT_COMPOSER_INSTALL', '@PATH@/autoload.php');
 }
 
 if (!defined('TEST_FILES_PATH')) {
@@ -19,3 +19,8 @@ ini_set('precision', '14');
 ini_set('serialize_precision', '14');
 
 require_once PHPUNIT_COMPOSER_INSTALL;
+require_once __DIR__ . '/_files/CoverageNamespacedFunctionTest.php';
+require_once __DIR__ . '/_files/CoveredFunction.php';
+require_once __DIR__ . '/_files/NamespaceCoveredFunction.php';
+require_once '@PATH@/Framework/Assert/Functions.php';
+require_once __DIR__ . '/autoload.php';