diff -up ./phpunit.rpm ./phpunit
--- ./phpunit.rpm	2021-08-02 09:09:31.000000000 +0200
+++ ./phpunit	2021-08-02 09:09:33.927568458 +0200
@@ -58,25 +58,12 @@ 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/PHPUnit9/autoload.php');
 }
 
 $options = getopt('', array('prepend:'));
@@ -89,4 +76,8 @@ unset($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/Xml/SchemaFinder.php.rpm ./src/Util/Xml/SchemaFinder.php
--- ./src/Util/Xml/SchemaFinder.php.rpm	2021-08-02 09:09:31.000000000 +0200
+++ ./src/Util/Xml/SchemaFinder.php	2021-08-02 09:09:33.927568458 +0200
@@ -48,6 +48,6 @@ final class SchemaFinder
             return __PHPUNIT_PHAR_ROOT__ . '/';
         }
 
-        return __DIR__ . '/../../../';
+        return __DIR__ . '/../../';
     }
 }
diff -up ./tests/bootstrap.php.rpm ./tests/bootstrap.php
--- ./tests/bootstrap.php.rpm	2021-08-02 09:09:33.928568455 +0200
+++ ./tests/bootstrap.php	2021-08-02 09:10:37.377383177 +0200
@@ -9,8 +9,8 @@
  */
 const TEST_FILES_PATH = __DIR__ . DIRECTORY_SEPARATOR . '_files' . DIRECTORY_SEPARATOR;
 
-$composer = file_exists(__DIR__ . '/../vendor/autoload.php');
-$phar     = file_exists(__DIR__ . '/autoload.php');
+$composer = true;
+$phar     = false;
 
 if ($composer && $phar) {
     print 'More than one test fixture autoloader is available, exiting.' . PHP_EOL;
@@ -26,10 +26,14 @@ if (!$composer && !$phar) {
 
 if ($composer) {
     if (!defined('PHPUNIT_COMPOSER_INSTALL')) {
-        define('PHPUNIT_COMPOSER_INSTALL', dirname(__DIR__) . '/vendor/autoload.php');
+        define('PHPUNIT_COMPOSER_INSTALL', '@PATH@/autoload.php');
     }
 
-    require_once __DIR__ . '/../vendor/autoload.php';
+    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 __DIR__ . '/autoload.php';
 }
 
 if ($phar) {