public void TestRemoveNode()
        {
            Node testNode = new Node();
            testNode.Id = -1;
            testNode.Latitude = 0;
            testNode.Longitude = 0;

            var source = new MemoryDataSource();
            source.AddNode(testNode);

            // test if the node is actually there.
            Assert.AreEqual(testNode, source.GetNode(-1));

            // remove the node.
            source.RemoveNode(-1);

            // test if the node is actually gone.
            Assert.IsNull(source.GetNode(-1));
        }