<?php

// ...

class LoginTest extends TestCase
{
    // ...

    public function test_remember_me_functionality()
    {
        $user = factory(User::class)->create([
            'id' => random_int(1, 100),
            'password' => bcrypt($password = 'i-love-laravel'),
        ]);

        $response = $this->post('/login', [
            'email' => $user->email,
            'password' => $password,
            'remember' => 'on',
        ]);

        $response->assertRedirect('/home');
        // cookie assertion goes here
        $this->assertAuthenticatedAs($user);
    }
}