Add From and FromGraph tests for FrozenGraph and for GraphTopologyAddition

The new tests are analogous to the existing Clone tests. Currently, only FrozenGraph implements From and FromGraph, but not GraphTopologyAddition, so the tests relying on GraphTopologyAddition are currently unused.

src/testing/graph_topology_addition_from_graph_testing.rs

@@ -0,0 +1,32 @@
+use crate::testing::fixtures;
+use crate::testing::fixtures::MakeTestGraph;
+use crate::traits::{FromGraph, GraphTopologyAddition};
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! graph_topology_addition_from_graph_tests {
+    ($T:ty, $U:ty) => {
+        $crate::graph_topology_addition_from_graph_tests!(@wrap $T, $U,
+            from_graph_mutation_independent,
+        );
+    };
+
+    (@wrap $T:ty, $U:ty, $($name:ident),* $(,)?) => {
+        $(
+            #[test]
+            fn $name() {
+                $crate::testing::graph_topology_addition_from_graph_testing::$name::<$T, $U>();
+            }
+        )*
+    };
+}
+
+pub fn from_graph_mutation_independent<G, H>()
+where
+    G: FromGraph + GraphTopologyAddition,
+    H: MakeTestGraph + GraphTopologyAddition,
+{
+    let (mut source, vertices, _) = H::single_edge();
+    let (mut graph, vertex_map, _) = G::from_graph(&source);
+    fixtures::assert_mutation_independent(&mut source, &mut graph, &vertices, |v| vertex_map[v]);
+}

src/testing/graph_topology_from_graph_testing.rs

@@ -0,0 +1,61 @@
+use std::fmt::Debug;
+
+use crate::testing::fixtures;
+use crate::testing::fixtures::MakeTestGraph;
+use crate::traits::{FromGraph, GraphTopology};
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! graph_topology_from_graph_tests {
+    ($T:ty, $U:ty) => {
+        $crate::graph_topology_from_graph_tests!(@wrap $T, $U,
+            from,
+            from_graph,
+        );
+    };
+
+    (@wrap $T:ty, $U:ty, $($name:ident),* $(,)?) => {
+        $(
+            #[test]
+            fn $name() {
+                $crate::testing::graph_topology_from_graph_testing::$name::<$T, $U>();
+            }
+        )*
+    };
+}
+
+pub fn from<G, H>()
+where
+    G: for<'a> From<&'a H> + GraphTopology,
+    H: MakeTestGraph,
+{
+    let (source, _, _, _) = H::standard();
+    let graph = G::from(&source);
+    assert_eq!(graph.vertex_count(), 10, "unexpected vertex count");
+    assert_eq!(graph.edge_count(), 18, "unexpected edge count");
+
+    let mut expected: Vec<_> = source.vertices().map(|v| source.degree(v)).collect();
+    let mut actual: Vec<_> = graph.vertices().map(|v| graph.degree(v)).collect();
+    expected.sort();
+    actual.sort();
+    assert_eq!(actual, expected, "degree sequence should match");
+}
+
+pub fn from_graph<G: FromGraph, H: MakeTestGraph>()
+where
+    G::Vertex: Debug,
+    G::Edge: Debug,
+    H::Vertex: Debug,
+    H::Edge: Debug,
+{
+    let (source, vertices, edges, _) = H::standard();
+    let (graph, vertex_map, edge_map) = G::from_graph(&source);
+    fixtures::assert_isomorphic(
+        &source,
+        &graph,
+        &vertices,
+        |v| vertex_map[v],
+        &edges,
+        |e| edge_map[e],
+    );
+}