Demonstration of `resetAuth` function

LoginTest.php

<?php

namespace Tests\Auth;

use Illuminate\Foundation\Auth\ThrottlesLogins;
use Illuminate\Foundation\Testing\DatabaseTransactions;
use Tests\TestCase;

class LoginTest extends TestCase
{
    use DatabaseTransactions, ThrottlesLogins;

    protected $auth_guard = 'web';

    // ...

    /** @test */
    public function it_should_throw_error_422_with_empty_form()
    {
        $this->postJson(route('login'), ['email' => '', 'password' => ''])
            ->assertStatus(422)
            ->assertJsonStructure(['message', 'errors' => ['email', 'password']]);

        $this->assertGuest($this->auth_guard);

        $this->resetAuth();
    }
  
    /** @test */
    public function it_should_throw_error_429_when_login_attempt_is_throttled()
    {
        $throttledUser = factory(User::class, 1)->create()->first();

        // corresponds to `Route::group(['middleware' => ['guest', 'throttle:10,5']], function () {`
        // ie: 10 attempts allowed per minute, with 5 minute cooldown
        foreach (range(0, 9) as $attempt) {
            $this->postJson(route('login'), ['email' => $throttledUser->email, 'password' => "{TestCase::AUTH_PASSWORD}_{$attempt}"]);
        }

        $this->postJson(route('login'), ['email' => $throttledUser->email, 'password' => TestCase::AUTH_PASSWORD . '6'])
            ->assertStatus(429)
            ->assertJson(['message' => 'Too Many Attempts.']);

        $this->resetAuth();
    }

}

/**
 * When making multiple requests in one test, the state of the Laravel API would not reset between the requests.
 * The AuthManager is a singleton in the laravel container, and it keeps a local cache of the resolved auth guards.
 * `$this->resetAuth()` is used to reset any session-remnants between unit tests.
 * Theory: https://stackoverflow.com/a/57941133/6141025
 */