/** * @expectedException UnderflowException */ public function testEdgesFailEdgeless() { // 1 -> 2 $graph = new Graph(); $v1 = $graph->createVertex(1); $v2 = $graph->createVertex(2); $e1 = $v1->createEdgeTo($v2); $e2 = $v1->createEdgeTo($v2); $graphCloneEdgeless = $graph->createGraphCloneEdgeless(); // nothing to return $graphCloneEdgeless->getEdgeClone($e1); }