n2 = new DefaultNode(r2);
n3 = new DefaultNode(r3);
Graph graph = new DefaultGraph();
graph.add(n1);
graph.add(n2);
graph.add(n3);
assertTrue(graph.getNodeCount() == 2);
Edge e1, e2;
e1 = new DefaultEdge(n1, n2, "Edge1", 2);
e2 = new DefaultEdge(n2, n3, "Edge2", 2);
graph.add(e1);
graph.add(e2);
assertTrue(graph.getEdgeCount() == 2);
graph.add(e1);
assertTrue(graph.getEdgeCount() == 2);
}