Laravel test not passing - laravel

Question

So I'm learning doing tests for my application and one of the tests it doesn't want to pass, and here it is the logic: Basically, when a user request the home page, I expect that the database list count would be 0, and this passed, then I expect also that the session has an error key of NoBook and here it fails. this is the code that i have tried:
class BookDisplayManagmentTest extends TestCase
{
use RefreshDatabase;
/** #test */
public function Show_error_message_when_there_is_no_book_to_display_in_index_page()
{
//Request the home page
$response = $this->get(route('home'));
// I expect the count on the database book equal 0
$this->assertCount(0, book::all());
//Then I also expect that the session will flash an error with key NoBook
$response->assertSessionHasErrors('NoBook');
}
}
But the problem I'm getting this error:
Session is missing expected key [errors]. Failed asserting that false is true.
And the code that add the session error:
<?php
namespace App\Http\Controllers;
use App\Books;
use Illuminate\Http\Request;
class IndexController extends Controller
{
/** #show index function */
public function index()
{
$book = Books::paginate(7);
if(!$book->count())
{
session()->now('NoBook','There is no books at the moment');
}
return view('index', compact('book'));
}
}

Answer 1

You are using session() which is adding a key to the session which is not an error key.
Therefore, since you are not passing an error from your Controller - then your test is "successfully" failing.
If you want to pass on an error to the session, you have to use MessageBag such as using the following code:
/** #show index function */
public function index()
{
$book = Books::paginate(7);
$errors = [];
if(!$book->count())
{
$errors['NoBook'] = 'There is no books at the moment';
}
return view('index', compact('book'))->withErrors($errors);
}