public function testGroupByAttribute()
{
$data = new Collection([['rating' => 1, 'url' => '1'], ['rating' => 1, 'url' => '1'], ['rating' => 2, 'url' => '2']]);
$result = $data->groupBy('rating');
$this->assertEquals([1 => [['rating' => 1, 'url' => '1'], ['rating' => 1, 'url' => '1']], 2 => [['rating' => 2, 'url' => '2']]], $result->toArray());
$result = $data->groupBy('url');
$this->assertEquals([1 => [['rating' => 1, 'url' => '1'], ['rating' => 1, 'url' => '1']], 2 => [['rating' => 2, 'url' => '2']]], $result->toArray());
}
