Testing loginform not working in featuretest?

Hi,

i'm trying to write a test that checks if i can authenticate with the correct user+pass when using my login form, and also check that i cannot login with missmatching user+pass. However i keep getting a failed test, saying i'm not authenticated even when user+pass is correct and it works as expected on the frontend.

AdminTest.php (Laravel 8, PHP 8.1)

namespace Tests\Feature;

use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Foundation\Testing\WithFaker;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\Session;
use Tests\TestCase;
use App\User;


/**
 * php artisan test --filter AdminTest
 */
class AdminTest extends TestCase
{
    /**
     * check if a user can login with correct credentials
     */
    public function test_user_can_login_with_correct_credentials()
    {
        $email = config('app.siteadmin.email');
        $password = 'hunter2';
        $user = \App\User::where('email', '=', $email)->first();
        //post email and password to signin page
        $this->followingRedirects();
        $response = $this->post(route('user.signin'), [
            'email' => $email,
            'password' => $password,
        ]);
        $response->dumpSession();
        $this->assertAuthenticatedAs($user);
    }
}	

The failes test output says that $user is null:

array:3 [
  "_previous" => array:1 [
    "url" => "http://127.0.0.1/login"
  ]
  "_token" => "gQjZFrYe7VGMJmUtPWlDCkA9Yd1ywZLUettUOLzC"
  "_flash" => array:2 [
    "new" => []
    "old" => []
  ]
]

   FAIL  Tests\Feature\AdminTest
  ⨯ user can login with correct credentials

  ---

  • Tests\Feature\AdminTest > user can login with correct credentials
  The current user is not authenticated.
  Failed asserting that null is not null.

  at \tests\Feature\AdminTest.php:74
     70▕             'email' => $email,
     71▕             'password' => $password,
     72▕         ]);
     73▕         $response->dumpSession();
  ➜  74▕         $this->assertAuthenticatedAs($user);
     75▕     }
     76▕
     77▕     /**
     78▕      * check if a user can access the admin panel with correct credentials

  1   \vendor\phpunit\phpunit\phpunit:98
      PHPUnit\TextUI\Command::main()


  Tests:  1 failed
  Time:   0.21s

I checked all the variables, routes and urls and they are correct. However i assume the login fails because the hidden "_token" from the original login form is never set, and cannot be passed on to to route('user.signin'). I cannot find a working example of how to test my login form in the laravel documentation or online, for what seems to me should be a basic fuction...?! Had a look at vendor/laravel/framework/src/Illuminate/Foundation/Testing/Concerns/MakesHttpRequests.php, but there seems to be nothing that explicitly handles "_token"...

What am i doing wrong, and what is the best way to test the login form here?