ClusterNode body = new ClusterNode();
head.addChild(body);
head.addChild(leaf1);
body.addChild(leaf2);
IClusterLevel leaf3 = new ClusterLeaf();
leaf3.addNode(outsideIn);
body.addChild(leaf3);
assertTrue(head.contains(a));
assertTrue(head.contains(b));
assertTrue(head.contains(outsideIn));
head.addNode(outsideOut);