public function testContainTPriorityLists()
{
$plist = new TPriorityList($this->plist);
$this->assertTrue($plist->contains($this->pfirst));
$this->assertTrue($plist->contains($this->pitem1));
$this->assertTrue($plist->contains($this->pitem2));
$this->assertTrue($plist->contains($this->pitem3));
$this->assertFalse($plist->contains($this->pitem5));
}