@Test
public void addMultipleEdgesToGraph() throws Exception {

    String [] edgesToAdd = {"x y", "u v"};
    edges = addEdgeToGraph(edgesToAdd);
    edge = new Edge<String>("x", "y");
    assertTrue(edges.contains(edge));
    edge = new Edge<String>("u", "v");
    assertTrue(edges.contains(edge));
}