AssetManager\Resolver\CollectionResolver::setCollections PHP Method

    public function setCollections($collections)
    {
        if (!is_array($collections) && !$collections instanceof Traversable) {
            throw new Exception\InvalidArgumentException(sprintf('%s: expects an array or Traversable, received "%s"', __METHOD__, is_object($collections) ? get_class($collections) : gettype($collections)));
        }
        if ($collections instanceof Traversable) {
            $collections = ArrayUtils::iteratorToArray($collections);
        }
        $this->collections = $collections;
    }

 /**
  * @expectedException \AssetManager\Exception\InvalidArgumentException
  */
 public function testSetCollectionFailsString()
 {
     $resolver = new CollectionResolver();
     $resolver->setCollections('invalid');
 }