Refactor ElementMap, removing its copy-on-write feature

src/testing/graph_topology_testing.rs

@@ -72,12 +72,22 @@ pub fn vertex_count<G: MakeTestGraph>() {
     assert_eq!(graph.vertex_count(), 10, "unexpected vertex count");
 }
 
-pub fn vertex_map<G: MakeTestGraph>() {
-    let (graph, v) = G::single_vertex();
-    let mut map = graph.vertex_map(27);
-    assert_eq!(map[v], 27, "unexpected value from default map read");
-    map[v] = 9;
-    assert_eq!(map[v], 9, "unexpected value from map after write");
+pub fn vertex_map<G: MakeTestGraph>()
+where
+    G::Vertex: Debug,
+{
+    let (graph, vertices, _, _) = G::standard();
+    let mut map = graph.vertex_map(88);
+    for (i, &v) in vertices.iter().enumerate() {
+        assert_eq!(
+            map[v], 88,
+            "unexpected value from default map read for vertex {v:?}"
+        );
+        map[v] = i;
+    }
+    for (i, &v) in vertices.iter().enumerate() {
+        assert_eq!(map[v], i, "unexpected value after write for vertex {v:?}");
+    }
 }
 
 pub fn edge_count_empty<G: MakeTestGraph>() {
@@ -90,12 +100,22 @@ pub fn edge_count<G: MakeTestGraph>() {
     assert_eq!(graph.edge_count(), 18, "unexpected edge count");
 }
 
-pub fn edge_map<G: MakeTestGraph>() {
-    let (graph, _, e) = G::single_edge();
-    let mut map = graph.edge_map(28);
-    assert_eq!(map[e], 28, "unexpected value from default map read");
-    map[e] = 8;
-    assert_eq!(map[e], 8, "unexpected value from map after write");
+pub fn edge_map<G: MakeTestGraph>()
+where
+    G::Edge: Debug,
+{
+    let (graph, _, edges, _) = G::standard();
+    let mut map = graph.edge_map(99);
+    for (i, &(e, _, _)) in edges.iter().enumerate() {
+        assert_eq!(
+            map[e], 99,
+            "unexpected value from default map read for edge {e:?}"
+        );
+        map[e] = i;
+    }
+    for (i, &(e, _, _)) in edges.iter().enumerate() {
+        assert_eq!(map[e], i, "unexpected value after write for edge {e:?}");
+    }
 }
 
 pub fn degree_zero<G: MakeTestGraph>() {