graph.addEdge("f", "h", null, 8, true);
graph.addEdge("g", "j", null, 2, false);
graph.addEdge("j", "i", null, 2, true);
graph.addEdge("h", "i", null, 8, true);
Vertex vertex = graph.getVertex("a");
Assert.assertNotNull(vertex);
Assert.assertEquals(vertex.getValue(), "a");
Assert.assertNull(graph.getVertex("1"));
Edge edge = graph.getEdge("a", "b");
Assert.assertNotNull(edge);