public function testBytesByMime()
{
list($handler, $repo, $auth, $keygen) = $this->getMocks();
$instance = new Storage($handler, $repo, $auth, $keygen);
$repo->shouldReceive('sumGroupBy')->twice()->andReturn(['image/jpeg' => 15116107, 'image/gif' => 14008053]);
$data = $instance->bytesByMime([], false);
$this->assertEquals(15116107 + 14008053, array_sum($data));
$data = $instance->bytesByMime();
$this->assertEquals(15116107, reset($data));
$this->assertEquals(14008053, next($data));
}