public function testValidator()
{
$collection = new Collection(['a', 'b', 'c']);
$collection->addValidator($validator = function ($value) {
return strlen($value) == 1;
});
$this->assertAttributeEquals(Collection::cast([$validator]), 'validators', $collection);
$this->expectsException(function () use($collection) {
$collection[] = 'invalid string!';
}, Exception::class);
}
