How to test login and regostration form?

Hi all, I spent a lot of time googling and searching, but I didn't find an answer to my question.

As you know, in Laravel there are some mock test for authentication and registration but they are not exactly what I want. Actually, I fell they test the code itself, not the form and bypass some of the workflows.

Example of pre-existing test for registration

public function new_users_can_register(): void
    {
        if (! Features::enabled(Features::registration())) {
            $this->markTestSkipped('Registration support is not enabled.');
        }

        $password = generateRandomPassword();

        $response = $this->post('/register', [
            'name' => 'John',
            'last_name' => 'Doe',
            'email' => '[email protected]',
            'password' => $password,
            'password_confirmation' => $password,
            'terms' => Jetstream::hasTermsAndPrivacyPolicyFeature(),
        ]);

        $this->assertAuthenticated();
        $response->assertRedirect(route('dashboard', absolute: false));
    }

However, in fact, I have added a config file with blacklisted words that cannot be used in the user name or last_name. Then, I have modified CreateNewUser like this:

<?php

declare(strict_types=1);

namespace App\Actions\Fortify;

use App\Models\User;
use App\Models\UserPreferences;
use Composer\InstalledVersions;
use Illuminate\Support\Facades\Hash;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Validator;
use Illuminate\Validation\ValidationException;
use Laravel\Fortify\Contracts\CreatesNewUsers;
use Laravel\Jetstream\Jetstream;

class CreateNewUser implements CreatesNewUsers
{
    use PasswordValidationRules;

    private array $errors = []; // Collect all errors

    /**
     * Validate and create a newly registered user.
     *
     * @param  array<string, string>  $input
     */
    public function create(array $input): User
    {
        Validator::make($input, [
            'name' => ['required', 'string', 'max:255'],
            'last_name' => ['required', 'string', 'max:255'],
            'email' => ['required', 'string', 'email', 'max:255', 'unique:users'],
            'password' => $this->passwordRules(),
            'terms' => Jetstream::hasTermsAndPrivacyPolicyFeature() ? ['accepted', 'required'] : '',
        ])->validate();

        // Check name and email against a blacklisted words
        $this->checkBlacklist($input['name'], $input['last_name'], $input['email']);

        if (! $this->errors) {
            $usrtmp = User::create([
                'name' => $input['name'],
                'last_name' => $input['last_name'],
                'email' => $input['email'],
                'password' => Hash::make($input['password']),
            ]);

            return $usrtmp;
        } else {
            throw ValidationException::withMessages($this->errors);
        }
    }

    /**
     * Check if the name or last name contains blacklisted terms.
     *
     * @throws ValidationException
     */
    protected function checkBlacklist(string $name, string $lastName, string $email)
    {
        $blacklist = config('blacklist.blacklist');

        foreach ($blacklist as $blacklistedName) {
            if (stripos($name, $blacklistedName) !== false) {
                $this->errors['name'] = 'The name contains a blacklisted word: ' . $blacklistedName;
                Log::warning(
                    'An attempt to register with name containing a blacklisted word: {' .
                        $blacklistedName .
                        '} detected',
                );
            }

            if (stripos($lastName, $blacklistedName) !== false) {
                $this->errors['last_name'] = 'The last name contains a blacklisted word: ' . $blacklistedName;
                Log::warning(
                    'An attempt to register with last name containing a blacklisted word: {' .
                        $blacklistedName .
                        '} detected',
                );
            }

            if (stripos($email, $blacklistedName) !== false) {
                $this->errors['email'] = 'The email contains a blacklisted word: ' . $blacklistedName;
                Log::warning(
                    'An attempt to register with email containing a blacklisted word: {' .
                        $blacklistedName .
                        '} detected',
                );
            }
        }

        if (! empty($this->errors)) {
            return $this->errors;
        } else {
            return 0;
        }
    }
}

When testing the form itself, it works as expected. However, if I run this test:

public function user_cannot_register_with_name_containing_blacklisted_word()
    {
        $this->withExceptionHandling();

        $blacklist = config('blacklist.blacklist');

        $key = array_rand($blacklist);
        $blacklistedWord = $blacklist[$key];
        $password = generateRandomPassword();

        $response = $this->post('/register', [
            'name' => $blacklistedWord,
            'last_name' => 'Doe',
            'email' => '[email protected]',
            'password' => $password,
            'password_confirmation' => $password,
            'terms' => Jetstream::hasTermsAndPrivacyPolicyFeature(),
        ]);

        $response->assertSee('The name or last name contains a blacklisted word');
    }

the response in the test is actually a redirect:

FAILED  Tests\Feature\User\RegistrationTest > user cannot register with name containing blacklisted word
  Expected: <!DOCTYPE html>\n
<html>\n
    <head>\n
        <meta charset="UTF-8" />\n
        <meta http-equiv="refresh" content="0;url='/dashboard'" />\n
\n
        <title>Redirecting to /dashboard</title>\n
    </head>\n
    <body>\n
        Redirecting to <a href="/dashboard">dashboard</a>.\n
    </body>\n
</html>

  To contain: The name or last name contains a blacklisted word

  at tests\Feature\User\RegistrationTest.php:90
     86▕             'password_confirmation' => $password,
     87▕             'terms' => Jetstream::hasTermsAndPrivacyPolicyFeature(),
     88▕         ]);
     89▕
  ➜  90▕         $response->assertSee('The name or last name contains a blacklisted word');
     91▕     }
     92▕ }
     93▕


  Tests:    1 failed, 1 skipped, 2 passed (5 assertions)
  Duration: 4.93s

Am I doing something wrong?

And how can I test the form itself? Something like Livewire::test()->fillForm()?