Prado\Collections\TPriorityList::insertAt PHP Method

    public function insertAt($index, $item)
    {
        if ($this->getReadOnly()) {
            throw new TInvalidOperationException('list_readonly', get_class($this));
        }
        if (($priority = $this->priorityAt($index, true)) !== false) {
            $this->insertAtIndexInPriority($item, $priority[1], $priority[0]);
        } else {
            throw new TInvalidDataValueException('list_index_invalid', $index);
        }
    }

 public function testInsertAtTPriorityList()
 {
     $plist = new TPriorityList($this->plist);
     $this->assertNull($plist->insertAt(0, $this->pitem3));
     $this->assertEquals(-10000000, $plist->priorityAt(0));
     try {
         $plist->insertAt(5, $this->pitem3);
         $this->fail('exception not raised when adding item at an out-of-range index');
     } catch (TInvalidDataValueException $e) {
     }
     $this->assertEquals(100, $plist->priorityAt(4));
 }