public function test_does_add_required_fields_for_morph_many_relation()
 {
     $this->populateDatabase();
     $model = new Models\Editor();
     $query = $model->query()->with('books');
     $modifier = $this->_getInstance($query, ['fields' => 'name']);
     $modifier->modify($query);
     $reqFields = $modifier->addRequiredFields(['name']);
     $this->assertEquals(2, count($reqFields));
     $this->assertContains('id', $reqFields);
     $this->assertContains('name', $reqFields);
     $this->assertEquals(1, count($query->find(1)->books));
 }