public function testGetParent()
{
Table9Peer::doDeleteAll();
$t0 = new Table9();
$this->assertFalse($t0->hasParent(), 'empty node has no parent');
$t1 = new Table9();
$t1->setTitle('t1')->setLeftValue(1)->setRightValue(8)->setLevel(0)->save();
$t2 = new Table9();
$t2->setTitle('t2')->setLeftValue(2)->setRightValue(7)->setLevel(1)->save();
$t3 = new Table9();
$t3->setTitle('t3')->setLeftValue(3)->setRightValue(4)->setLevel(2)->save();
$t4 = new Table9();
$t4->setTitle('t4')->setLeftValue(5)->setRightValue(6)->setLevel(2)->save();
$this->assertNull($t1->getParent($this->con), 'getParent() return null for root nodes');
$this->assertEquals($t2->getParent($this->con), $t1, 'getParent() correctly retrieves parent for nodes');
$this->assertEquals($t3->getParent($this->con), $t2, 'getParent() correctly retrieves parent for leafs');
$this->assertEquals($t4->getParent($this->con), $t2, 'getParent() retrieves the same parent for two siblings');
}