public function testEmptyPersistedAttributesReturnsEverythingInQuery()
 {
     $now = Carbon::now();
     DB::table('vehicles')->insert([['type' => 'car', 'color' => 'red', 'cruft' => 'red is my favorite', 'owner_id' => null, 'created_at' => $now, 'updated_at' => $now]]);
     $car = Car::withAllPersisted([], function () {
         return Car::all()->first();
     });
     $this->assertEquals('red is my favorite', $car->cruft);
 }