public function testGraphMixed()
{
// 1 -- 2 -> 3
$graph = new Graph();
$graph->createVertex(1)->createEdge($graph->createVertex(2));
$graph->getVertex(2)->createEdgeTo($graph->createVertex(3));
$alg = new AlgorithmDirected($graph);
$this->assertTrue($alg->hasDirected());
$this->assertTrue($alg->hasUndirected());
$this->assertTrue($alg->isMixed());
}
