public function testIsAssoc()
{
isFalse(Arr::isAssoc(array('a', 'b', 'c')));
isFalse(Arr::isAssoc(array("0" => 'a', "1" => 'b', "2" => 'c')));
isTrue(Arr::isAssoc(array("1" => 'a', "0" => 'b', "2" => 'c')));
isTrue(Arr::isAssoc(array("a" => 'a', "b" => 'b', "c" => 'c')));
}