public function test_associate_students()
{
$classroom = factory(Classroom::class)->create();
$students = factory(Student::class, 30)->create();
$data = ['id' => $classroom->id, 'students' => []];
$random = $students->random(3)->each(function ($student) use(&$data) {
$data['students'][] = ['id' => $student->id];
});
$repo = App::make(ClassroomRepository::class);
$repo->associateStudents($classroom, $data);
foreach ($data['students'] as $key => $value) {
$this->seeInDatabase('classroom_student', ['classroom_id' => $classroom->id, 'student_id' => $data['students'][$key]['id']]);
}
}