### Question:
DefaultVertexPositioning implements VertexPositioning { void deReverseEdges(final ReorderedGraph graph) { for (final OrientedEdge edge : graph.getEdges()) { if (edge.isReversed()) { edge.reverse(); } } }  @Override void calculateVerticesPositions(final ReorderedGraph graph,
                                           final LayerArrangement arrangement); boolean removeVirtualVertex(final OrientedEdge edge,
                                       final List<OrientedEdge> edges,
                                       final Set<Vertex> vertices); void removeVirtualVertices(final List<OrientedEdge> edges,
                                      final Set<Vertex> vertices);  }### Answer:
@Test public void testDeReverseEdges() { final LayeredGraph graph = new LayeredGraph(); final OrientedEdgeImpl e1 = new OrientedEdgeImpl("1", "2", true); final OrientedEdgeImpl e2 = new OrientedEdgeImpl("2", "3", false); final OrientedEdgeImpl e3 = new OrientedEdgeImpl("2", "4", true); graph.addEdge(e1); graph.addEdge(e2); graph.addEdge(e3); tested.deReverseEdges(graph); assertFalse(e1.isReversed()); assertFalse(e2.isReversed()); assertFalse(e3.isReversed()); }