PHP Deprecated: ucfirst(): Passing null to parameter #1 ($string) of type string is deprecated

[Klap-in]

..../dokuwiki/lib/plugins/indexmenu$ ../../../bin/plugin.php dev addTest
PHP Deprecated:  ucfirst(): Passing null to parameter #1 ($string) of type string is deprecated in /home/gerrit/Sites/dokuwiki/dokuwiki/lib/plugins/dev/Skeletor.php on line 165
✓ .github/workflows/dokuwiki.yml created
✓ _test/GeneralTest.php created

dokuwiki-plugin-dev/cli.php

Lines 90 to 92 in 7c3b7a0

	case 'addTest':
	$test = array_shift($args);
	return $this->cmdAddTest($test);

dokuwiki-plugin-dev/cli.php

Lines 286 to 289 in 7c3b7a0

	protected function cmdAddTest($test = '')
	{
	$skeletor = Skeletor::fromDir(getcwd());
	$skeletor->addTest($test);

dokuwiki-plugin-dev/Skeletor.php

Line 165 in 7c3b7a0

$test = ucfirst($test);

Probably the $this->args array which is used in cli.php is empty, and therefore resulting in a null. An option is casting to string?