roundcubemail/plugins/virtuser_query/tests/VirtuserQuery.php

<?php

class VirtuserQuery_Plugin extends PHPUnit\Framework\TestCase
{
    public static function setUpBeforeClass(): void
    {
        include_once __DIR__ . '/../virtuser_query.php';
    }

    /**
     * Plugin object construction test
     */
    public function test_constructor()
    {
        $rcube  = rcube::get_instance();
        $plugin = new virtuser_query($rcube->plugins);

        $this->assertInstanceOf('virtuser_query', $plugin);
        $this->assertInstanceOf('rcube_plugin', $plugin);
    }
}