### Question:
OTPServiceImpl implements OTPService.Iface { @Override public GraphVerticesResponse GetVertices(GraphVerticesRequest req) throws TException { LOG.debug("GetVertices called"); long startTime = System.currentTimeMillis(); GraphVerticesResponse res = new GraphVerticesResponse(); Graph g = graphService.getGraph(); res.setVertices(makeGraphVertices(g)); res.setCompute_time_millis(System.currentTimeMillis() - startTime); return res; }  @Override GraphVerticesResponse GetVertices(GraphVerticesRequest req); @Override GraphEdgesResponse GetEdges(GraphEdgesRequest req); @Override FindNearestVertexResponse FindNearestVertex(FindNearestVertexRequest req); @Override BulkFindNearestVertexResponse BulkFindNearestVertex(BulkFindNearestVertexRequest req); @Override FindNearestEdgesResponse FindNearestEdges(FindNearestEdgesRequest req); @Override BulkFindNearestEdgesResponse BulkFindNearestEdges(BulkFindNearestEdgesRequest req); @Override FindPathsResponse FindPaths(FindPathsRequest req); @Override BulkPathsResponse BulkFindPaths(BulkPathsRequest req);  }### Answer:
@Test public void testGetGraphVertices() throws TException { GraphVerticesRequest req = new GraphVerticesRequest(); req.validate(); GraphVerticesResponse res = serviceImpl.GetVertices(req); Set<Integer> expectedVertexIds = new HashSet<Integer>(); for (Vertex v : graph.getVertices()) { expectedVertexIds.add(v.getIndex()); } Set<Integer> actualVertexIds = new HashSet<Integer>(res.getVerticesSize()); for (GraphVertex gv : res.getVertices()) { actualVertexIds.add(gv.getId()); } assertTrue(expectedVertexIds.equals(actualVertexIds)); }