@Test(expectedExceptions = RuntimeException.class)
public void testInvalidEdges() {

    NodeImpl n1 = new NodeImpl("0");
    NodeImpl n2 = new NodeImpl("1");
    EdgeImpl e1 = new EdgeImpl("0", n1, n2, 0, 1.0, true);
    EdgeStore edgeStore = new EdgeStore();
    edgeStore.add(e1);
}