public function testGettingMaxItemsFromCollection()
{
$c = new Collection([(object) ['foo' => 10], (object) ['foo' => 20]]);
$this->assertEquals(20, $c->max('foo'));
$c = new Collection([['foo' => 10], ['foo' => 20]]);
$this->assertEquals(20, $c->max('foo'));
$c = new Collection([1, 2, 3, 4, 5]);
$this->assertEquals(5, $c->max());
$c = new Collection();
$this->assertNull($c->max());
}