test: add compatibility layer for phpunit

test/bootstrap.php

@@ -4,6 +4,9 @@ use Icinga\Module\Director\Test\Bootstrap;
 
 call_user_func(function () {
     $basedir = dirname(__DIR__);
+    if (! class_exists('PHPUnit_Framework_TestCase')) {
+        require_once __DIR__ . '/phpunit-compat.php';
+    }
     require_once $basedir . '/library/Director/Test/Bootstrap.php';
     Bootstrap::cli($basedir);
 });

test/phpunit-compat.php

@@ -0,0 +1,10 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @codingStandardsIgnoreStart
+ */
+class PHPUnit_Framework_TestCase extends TestCase
+{
+}