public function testNullifyParentColumnOnNewNodes()
{
$node = new Cluster(['name' => 'Root 3']);
$node->parent_id = null;
$node->save();
$node->reload();
$this->assertNull($node->parent()->first());
$this->assertEquals(0, $node->getLevel());
$this->assertEquals(13, $node->getLeft());
$this->assertEquals(14, $node->getRight());
$this->assertTrue(Cluster::isValidNestedSet());
}