Temporary User for testing

Hi all, I'm trying to understand which is the best practice to test an API with PHPUnit under Laravel.

    $user = factory(User::class)->create();

    $response = $this->actingAs($user)
                     ->get('/xyz/aaa/bbb/ccc');

    $response->assertStatus(200);

My /xyz route is under auth, so I need to access if acting as an authenticated user.

Creating a new user is the answer (I think) but if I launch 10 times the test, I'll create 10 users (of course !)

Which is the right (or the best) way to create a "temporary" user to test my API ?

Should I leverage on SetUp and TearDown methods ? Or there's a better way ?

Thanks in Advance FabioG