Skip the read-only directory assertion when the tests run as root

Root can write to a directory with mode 0500, so is_writable() is true
there. The Docker jobs run the tests as root.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: 2 people

tests/PHPStan/Process/Restart/OpcacheSettingsTest.php

@@ -8,9 +8,11 @@
 use function array_keys;
 use function chmod;
 use function fileowner;
+use function function_exists;
 use function is_dir;
 use function is_link;
 use function mkdir;
+use function posix_geteuid;
 use function rmdir;
 use function scandir;
 use function symlink;
@@ -190,7 +192,10 @@ public function testIsPrivateDirectory(): void
 		$this->assertFalse(OpcacheSettings::isPrivateDirectory($base . '/shared', $userId));
 
 		mkdir($base . '/readonly', 0500);
-		$this->assertFalse(OpcacheSettings::isPrivateDirectory($base . '/readonly', $userId));
+		// root can write to any directory, so is_writable() does not see the mode
+		if (function_exists('posix_geteuid') && posix_geteuid() !== 0) {
+			$this->assertFalse(OpcacheSettings::isPrivateDirectory($base . '/readonly', $userId));
+		}
 		chmod($base . '/readonly', 0700);
 
 		symlink($base . '/private', $base . '/link');