public function test_complete_matter()
{
$student = factory(Student::class)->create();
$classroom = factory(Classroom::class)->create();
$matter = factory(Matter::class)->create();
$classroomMatter = factory(ClassroomMatter::class)->create(['classroom_id' => $classroom->id, 'matter_id' => $matter->id]);
$student->classrooms()->attach($classroom);
$this->assertTrue($student->completeMatter($classroom->id, $matter->id));
}