AuthenticationTest.php

    public function test_admin_login()
    {
        $password = 'admin';

        $admin = AdminFactory::create(["password" => $password]);

        $this->visit("/admin");
        $this->fillField("_username", $admin->getUsername());
        $this->fillField("_password", 'admin');
        $this->pressButton('Anmelden');

        $this->assertContains("Abmelden", $this->getPageContent());
    }