public function test_create_student()
{
$student = factory(Student::class)->create(['sex' => 'female']);
$this->assertInstanceOf(Student::class, $student);
$this->assertInstanceOf(Carbon::class, $student->created_at);
$this->assertInstanceOf(Carbon::class, $student->updated_at);
$this->seeInDatabase('students', ['name' => $student->name, 'sex' => $student->sex]);
$this->assertEquals($student->getPayer(), $this->getPayer($student));
}