public function test_update_by_put()
{
$billet = factory(Billet::class)->create();
$data = ['amount' => 100, 'refer' => $billet->refer, 'student_id' => $billet->student_id];
$return = $this->put('api/v1/billet/' . $billet->id, $data);
$this->seeStatusCode(200);
$this->seeJson(['amount' => 100]);
$this->assertInstanceOf(Billet::class, $return->response->original);
$this->seeInDatabase('billets', ['id' => $return->response->original->id]);
}