public function testDefault()
 {
     $t = new Table9();
     $t->setTreeLeft('123');
     $this->assertEquals($t->getLeftValue(), '123', 'nested_set adds a getLeftValue() method');
     $t->setTreeRight('456');
     $this->assertEquals($t->getRightValue(), '456', 'nested_set adds a getRightValue() method');
     $t->setLevel('789');
     $this->assertEquals($t->getLevel(), '789', 'nested_set adds a getLevel() method');
 }