Prado\Collections\TPriorityList::insertBefore PHP Method

    public function insertBefore($indexitem, $item)
    {
        if ($this->getReadOnly()) {
            throw new TInvalidOperationException('list_readonly', get_class($this));
        }
        if (($priority = $this->priorityOf($indexitem, true)) === false) {
            throw new TInvalidDataValueException('list_item_inexistent');
        }
        $this->insertAtIndexInPriority($item, $priority[1], $priority[0]);
        return $priority[2];
    }

 public function testRemoveTPriorityList()
 {
     $plist = new TPriorityList($this->plist);
     $this->assertEquals(2, $plist->remove($this->pitem2));
     $this->assertEquals(1, $plist->getPriorityCount());
     $plist = new TPriorityList($this->plist);
     try {
         $plist->remove($this->pitem5);
         $this->fail('Exception not raised: TInvalidDataValueException: The item cannot be found in the list');
     } catch (TInvalidDataValueException $v) {
     }
     try {
         $plist->remove($this->pitem3, null);
         $this->fail('Exception not raised: TInvalidDataValueException: The item cannot be found in the list');
     } catch (TInvalidDataValueException $v) {
     }
     try {
         $plist->remove($this->pitem1, 100);
         $this->fail('Exception not raised: TInvalidDataValueException: The item cannot be found in the list');
     } catch (TInvalidDataValueException $v) {
     }
     $plist->insertBefore($this->pitem3, $this->pitem4);
     $this->assertEquals(4, $plist->remove($this->pitem3, 100));
 }