@Test
public void addMultipleEdgesToBuilder() {

    ArrayList<String> col = new ArrayList<String>();
    col.add("1 2");
    col.add("3 4");
    edges = addEdgesToBuilder(col);
    edge = new Edge<String>("1", "2");
    assertTrue(edges.contains(edge));
    edge = new Edge<String>("3", "4");
    assertTrue(edges.contains(edge));
}