public function testGroupedNodes()
{
$root = new Node();
$ab = $root->child_with_name('a:b');
$this->assertSame($ab, $root->get_task('a:b'));
$a = $ab->get_parent();
$this->assertSame($a, $root->get_task('a'));
$this->assertEquals(array('a:b' => $ab), $a->get_tasks());
$this->assertSame($root, $a->get_parent());
$this->assertSame($root, $ab->get_root());
$this->assertEquals(array('a' => $a, 'a:b' => $ab), $root->get_tasks());
}