Move the disconnected test graph to the more general graph_topology_test_fixtures macro

src/testing/graph_topology_testing.rs

@@ -87,6 +87,17 @@ macro_rules! graph_topology_test_fixtures {
             ];
             (graph, vertices, edges, incidences)
         }
+
+        #[allow(dead_code)]
+        fn make_test_graph_disconnected()
+            -> ($T, [<$T as $crate::traits::GraphTopology>::Vertex; 3]) {
+            use $crate::traits::GraphTopology;
+            let mut graph = <$T>::new();
+            let vertices: [<$T as $crate::traits::GraphTopology>::Vertex; 3] =
+                core::array::from_fn(|_| graph.add_vertex());
+            graph.add_edge(vertices[1], vertices[2]);
+            (graph, vertices)
+        }
     };
 }