Added regression test to prevent endless loop in subprocess

Author: staabm

tests/end-to-end/regression/6304.phpt

@@ -0,0 +1,29 @@
+--TEST--
+https://github.com/sebastianbergmann/phpunit/issues/6304
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = '--display-phpunit-deprecations';
+$_SERVER['argv'][] = __DIR__ . '/6304/Issue6304Test.php';
+
+require __DIR__ . '/../../bootstrap.php';
+
+(new PHPUnit\TextUI\Application)->run($_SERVER['argv']);
+--EXPECTF--
+PHPUnit %s by Sebastian Bergmann and contributors.
+
+Runtime: %s
+
+.                                                                   1 / 1 (100%)
+
+Time: %s, Memory: %s MB
+
+There were 2 PHPUnit test runner deprecations:
+
+1) Metadata found in doc-comment for class Issue6304Test. Metadata in doc-comments is deprecated and will no longer be supported in PHPUnit 12. Update your test code to use attributes instead.
+
+2) Metadata found in doc-comment for class Issue6304Test. Metadata in doc-comments is deprecated and will no longer be supported in PHPUnit 12. Update your test code to use attributes instead.
+
+OK, but there were issues!
+Tests: 1, Assertions: 1, PHPUnit Deprecations: 2.

tests/end-to-end/regression/6304/Issue6304Test.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @group test
+ *
+ * @runTestsInSeparateProcesses
+ */
+final class Issue6304Test extends TestCase
+{
+    public function testOne(): void
+    {
+        $this->assertTrue(true);
+    }
+}