diff --git a/src/testing/graph_topology_testing.rs b/src/testing/graph_topology_testing.rs
index 400290c..d949a5e 100644
--- a/src/testing/graph_topology_testing.rs
+++ b/src/testing/graph_topology_testing.rs
@@ -128,6 +128,19 @@ macro_rules! graph_topology_tests {
             assert_eq!(graph.vertex_count(), 10, "unexpected vertex count");
         }
 
+        #[test]
+        fn vertex_map() {
+            use $crate::traits::GraphTopology;
+            let mut graph = <$T>::new();
+            let v1 = graph.add_vertex();
+            let mut map = graph.vertex_map(27);
+            assert_eq!(map[v1], 27, "unexpected value from default map read");
+            map[v1] = 9;
+            assert_eq!(map[v1], 9, "unexpected value from map after write");
+            let v2 = graph.add_vertex();
+            assert_eq!(map[v2], 27, "unexpected value from default map read for new vertex");
+        }
+
         #[test]
         fn add_edge() {
             use $crate::traits::GraphTopology;
@@ -152,6 +165,21 @@ macro_rules! graph_topology_tests {
             assert_eq!(graph.edge_count(), 18, "unexpected edge count");
         }
 
+        #[test]
+        fn edge_map() {
+            use $crate::traits::GraphTopology;
+            let mut graph = <$T>::new();
+            let v1 = graph.add_vertex();
+            let v2 = graph.add_vertex();
+            let e1 = graph.add_edge(v1, v2);
+            let mut map = graph.edge_map(27);
+            assert_eq!(map[e1], 27, "unexpected value from default map read");
+            map[e1] = 9;
+            assert_eq!(map[e1], 9, "unexpected value from map after write");
+            let e2 = graph.add_edge(v1, v2);
+            assert_eq!(map[e2], 27, "unexpected value from default map read for new vertex");
+        }
+
         #[test]
         fn degree_zero() {
             use $crate::traits::GraphTopology;