@Test
public void testGetMutualEdge() {

    GraphStore graphStore = GraphGenerator.generateSmallGraphStore();
    GraphViewStore store = graphStore.viewStore;
    GraphViewImpl view = store.createView();
    addSomeElements(graphStore, view);
    DirectedSubgraph graph = store.getDirectedGraph(view);
    for (Edge e : graph.getEdges()) {
        if (graph.getEdge(e.getTarget(), e.getSource()) != null) {
            Edge m = graph.getMutualEdge(e);
            Assert.assertSame(m, graph.getEdge(e.getTarget(), e.getSource()));
        } else {
            Assert.assertNull(graph.getMutualEdge(e));
        }
    }
}