public void TestSparseRemoval1Routing()
        {
            // use one edge definition everywhere.
            var tagsIndex = new TagsTableCollectionIndex();
            var tags      = new TagsCollection(new Tag("highway", "residential"));
            var edge      = new LiveEdge();

            edge.Forward = true;
            edge.Tags    = tagsIndex.Add(tags);

            var  graph   = new MemoryDynamicGraph <LiveEdge>();
            uint vertex1 = graph.AddVertex(51.267797f, 4.8013623f);
            uint vertex2 = graph.AddVertex(51.267702f, 4.8013396f);
            uint vertex3 = graph.AddVertex(51.267592f, 4.8013024f);

            graph.AddEdge(vertex1, vertex2, edge, null);
            graph.AddEdge(vertex2, vertex3, edge, null);
            graph.AddEdge(vertex3, vertex2, edge, null);

            // save vertex coordinates for later use.
            float latitude, longitude;

            graph.GetVertex(vertex1, out latitude, out longitude);
            var vertex1Coordinate = new GeoCoordinate(latitude, longitude);

            graph.GetVertex(vertex2, out latitude, out longitude);
            var vertex2Coordinate = new GeoCoordinate(latitude, longitude);

            graph.GetVertex(vertex3, out latitude, out longitude);
            var vertex3Coordinate = new GeoCoordinate(latitude, longitude);

            // execute pre-processor.
            var preProcessor = new LiveEdgePreprocessor(graph);

            preProcessor.Start();

            // create router.
            var source = new DynamicGraphRouterDataSource <LiveEdge>(
                graph, tagsIndex);
            var router = Router.CreateLiveFrom(source, new OsmRoutingInterpreter());

            // test some basic routing requests.
            // 1 -> 3: 1 -> 2 -> 3.
            var resolved1 = router.Resolve(Vehicle.Car, vertex1Coordinate);
            var resolved3 = router.Resolve(Vehicle.Car, vertex3Coordinate);
            var route     = router.Calculate(Vehicle.Car, resolved1, resolved3);

            // verify the simple route result.
            Assert.IsNotNull(route);
            Assert.AreEqual(3, route.Segments.Length);
            Assert.AreEqual(vertex1Coordinate.Latitude, route.Segments[0].Latitude);
            Assert.AreEqual(vertex1Coordinate.Longitude, route.Segments[0].Longitude);
            Assert.AreEqual(vertex2Coordinate.Latitude, route.Segments[1].Latitude);
            Assert.AreEqual(vertex2Coordinate.Longitude, route.Segments[1].Longitude);
            Assert.AreEqual(vertex3Coordinate.Latitude, route.Segments[2].Latitude);
            Assert.AreEqual(vertex3Coordinate.Longitude, route.Segments[2].Longitude);

            // 1 -> 2: 1 -> 2.
            router    = Router.CreateLiveFrom(source, new OsmRoutingInterpreter());
            resolved1 = router.Resolve(Vehicle.Car, vertex1Coordinate);
            var resolved2 = router.Resolve(Vehicle.Car, vertex2Coordinate);

            route = router.Calculate(Vehicle.Car, resolved1, resolved2);

            // verify the simple route result.
            Assert.IsNotNull(route);
            Assert.AreEqual(2, route.Segments.Length);
            Assert.AreEqual(vertex1Coordinate.Latitude, route.Segments[0].Latitude);
            Assert.AreEqual(vertex1Coordinate.Longitude, route.Segments[0].Longitude);
            Assert.AreEqual(vertex2Coordinate.Latitude, route.Segments[1].Latitude);
            Assert.AreEqual(vertex2Coordinate.Longitude, route.Segments[1].Longitude);
        }