src/algorithms.rs

@@ -558,8 +558,7 @@ where
 
     let mut visited = graph.vertex_map(false);
     visited[source] = true;
-    let mut predecessor: ElementMap<G::Vertex, Option<(G::Vertex, G::Edge)>> =
+    let mut predecessor = graph.vertex_map(None);
-        graph.vertex_map(None);
     let mut queue = VecDeque::from([source]);
 
     while let Some(v) = queue.pop_front() {

src/lib.rs

@@ -6,10 +6,10 @@
 //! Currently supported are:
 //!
 //! * Undirected graph types [`Graph`], [`AppendGraph`], and [`FrozenGraph`] built on a flat,
-//! index-based adjacency list,
+//!   index-based adjacency list,
 //! * [`ElementMap`] to freely associate custom data with vertices and edges,
 //! * Connectivity and pathing algorithms: [Dijkstra's algorithm], [DFS], and [BFS] in different
-//! variants,
+//!   variants,
 //! * Exposed [`traits`] to implement custom graph data structures or algorithms.
 //!
 //! # Usage example

src/maps.rs

@@ -89,7 +89,7 @@ impl<E: Copy, T: Clone> ElementMap<E, T> {
     /// ```
     pub fn map<U: Clone>(&self, f: impl Fn(&T) -> U) -> ElementMap<E, U> {
         ElementMap {
-            data: self.data.iter().map(|v| f(v)).collect(),
+            data: self.data.iter().map(&f).collect(),
             default: f(&self.default),
             to_index: self.to_index,
         }

src/models/frozen_graph.rs

@@ -308,8 +308,8 @@ mod tests {
     #[test]
     fn opposite_symmetry() {
         let (graph, ..) = FrozenGraph::standard();
-        for i in 0..graph.incidences.len() {
+        for (i, inc) in graph.incidences.iter().enumerate() {
-            let opp = graph.incidences[i].opposite;
+            let opp = inc.opposite;
             assert_ne!(opp, i, "incidence should not equal its own opposite");
             assert_eq!(
                 graph.incidences[opp].opposite, i,

src/testing/fixtures.rs

@@ -5,6 +5,8 @@ use crate::models::{AppendGraph, FrozenGraph};
 use crate::traits::{GraphTopology, GraphTopologyAddition, GraphTopologyConversion, Incidence};
 
 pub trait MakeTestGraph: GraphTopology + Sized {
+    // Since this is only a test fixture, the complex return type here is deemed acceptable.
+    #[allow(clippy::type_complexity)]
     fn standard() -> (
         Self,
         [Self::Vertex; 10],
@@ -293,12 +295,12 @@ pub fn assert_standard_unweighted_predecessors_v0<V: Debug + Copy + PartialEq>(
         vec![Some(vertices[4])],
         vec![Some(vertices[5]), Some(vertices[6]), Some(vertices[7])],
     ];
-    for i in 0..10 {
+    assert_eq!(vertices.len(), expected.len());
+    for (&v, exp) in vertices.iter().zip(&expected) {
         assert!(
-            expected[i].contains(&actual[vertices[i]]),
+            exp.contains(&actual[v]),
-            "unexpected predecessor {:?} of vertex {:?}",
+            "unexpected predecessor {:?} of vertex {v:?}",
-            actual[vertices[i]],
+            actual[v]
-            vertices[i]
         );
     }
 }
@@ -320,8 +322,7 @@ where
 {
     let path = path_option.unwrap_or_else(|| {
         panic!(
-            "path should exist between source vertex {:?} and connected targets {:?}",
+            "path should exist between source vertex {source:?} and connected targets {targets:?}"
-            source, targets
         )
     });
 

src/testing/graph_topology_addition_testing.rs

@@ -43,10 +43,11 @@ pub fn reserve_vertices_increases_capacity<G: GraphTopologyAddition>() {
 }
 
 pub fn reserve_vertices_prevents_reallocation_on_add<G: GraphTopologyAddition>() {
+    const N: usize = 10;
     let mut graph = G::default();
-    graph.reserve_vertices(10);
+    graph.reserve_vertices(N);
     let capacity_before = graph.vertex_capacity();
-    for _ in 0..10 {
+    for _ in 0..N {
         graph.add_vertex();
     }
     assert_eq!(
@@ -78,12 +79,13 @@ pub fn reserve_edges_increases_capacity<G: GraphTopologyAddition>() {
 }
 
 pub fn reserve_edges_prevents_reallocation_on_add<G: GraphTopologyAddition>() {
+    const N: usize = 10;
     let mut graph = G::default();
     let u = graph.add_vertex();
     let v = graph.add_vertex();
-    graph.reserve_edges(10);
+    graph.reserve_edges(N);
     let capacity_before = graph.edge_capacity();
-    for _ in 0..10 {
+    for _ in 0..N {
         graph.add_edge(u, v);
     }
     assert_eq!(

src/testing/graph_topology_deletion_testing.rs

@@ -262,7 +262,8 @@ where
     G::Vertex: Debug,
 {
     let (mut graph, vertices, _, _) = G::standard();
-    graph.delete_vertex(vertices[2]);
+    let del = vertices[2];
+    graph.delete_vertex(del);
     assert_eq!(
         graph.vertex_count(),
         9,
@@ -274,17 +275,12 @@ where
         "unexpected vertex iterator count after delete"
     );
     for v in graph.vertices() {
-        assert_ne!(
+        assert_ne!(v, del, "deleted vertex {del:?} appeared in iterator");
-            v, vertices[2],
-            "deleted vertex {:?} appeared in iterator",
-            vertices[2]
-        );
     }
-    for i in [0, 1, 3, 4, 5, 6, 7, 8, 9] {
+    for &v in vertices.iter().filter(|&&u| u != del) {
         assert!(
-            graph.vertices().any(|v| v == vertices[i]),
+            graph.vertices().any(|u| u == v),
-            "expected vertex {:?} missing from iterator after delete",
+            "expected vertex {v:?} missing from iterator after delete"
-            vertices[i]
         );
     }
 }
@@ -295,9 +291,9 @@ where
     G::Edge: Debug,
 {
     let (mut graph, _, edges, _) = G::standard();
-    let e = edges[2].0;
+    let del = edges[2].0;
-    graph.delete_edge(e);
+    graph.delete_edge(del);
-    for &(f, v0, v1) in edges.iter().filter(|&&(f, _, _)| f != e) {
+    for &(f, v0, v1) in edges.iter().filter(|&&(f, _, _)| f != del) {
         let (u0, u1) = graph.incident_vertices(f);
         assert!(
             (u0 == v0 && u1 == v1) || (u0 == v1 && u1 == v0),
@@ -340,13 +336,15 @@ where
     G::Edge: Debug,
 {
     let (mut graph, vertices, edges, incidences) = G::standard();
-    graph.delete_edge(edges[2].0);
+    let del = edges[2].0;
-    for i in 0..10 {
+    graph.delete_edge(del);
-        let mut expected: Vec<_> = incidences[i]
+    assert_eq!(vertices.len(), incidences.len());
+    for (&v, incs) in vertices.iter().zip(&incidences) {
+        let mut expected = incs
             .iter()
-            .filter_map(|x| (x.edge != edges[2].0).then_some(x.edge))
+            .filter_map(|x| (x.edge != del).then_some(x.edge))
             .collect();
-        assert_incident_edges_after_delete(&graph, vertices[i], &mut expected);
+        assert_incident_edges_after_delete(&graph, v, &mut expected);
     }
 }
 
@@ -356,13 +354,14 @@ where
     G::Edge: Debug,
 {
     let (mut graph, vertices, _, incidences) = G::standard();
-    graph.delete_vertex(vertices[2]);
+    let del = vertices[2];
-    for i in [0, 1, 3, 4, 5, 6, 7, 8, 9] {
+    graph.delete_vertex(del);
-        let mut expected: Vec<_> = incidences[i]
+    for (&v, incs) in vertices.iter().zip(&incidences).filter(|&(&u, _)| u != del) {
+        let mut expected = incs
             .iter()
-            .filter_map(|x| (x.vertex != vertices[2]).then_some(x.edge))
+            .filter_map(|x| (x.vertex != del).then_some(x.edge))
             .collect();
-        assert_incident_edges_after_delete(&graph, vertices[i], &mut expected);
+        assert_incident_edges_after_delete(&graph, v, &mut expected);
     }
 }
 
@@ -372,14 +371,11 @@ where
     G::Edge: Debug,
 {
     let (mut graph, vertices, _, incidences) = G::standard();
-    graph.delete_vertex(vertices[2]);
+    let del = vertices[2];
-    for i in [0, 1, 3, 4, 5, 6, 7, 8, 9] {
+    graph.delete_vertex(del);
-        let remaining = incidences[i]
+    for (&v, incs) in vertices.iter().zip(&incidences).filter(|&(&u, _)| u != del) {
-            .iter()
+        let remaining = incs.iter().filter(|x| x.vertex != del).cloned().collect();
-            .filter(|x| x.vertex != vertices[2])
+        assert_vertex_incidences(&graph, v, remaining);
-            .cloned()
-            .collect();
-        assert_vertex_incidences(&graph, vertices[i], remaining);
     }
 }
 
@@ -389,14 +385,12 @@ where
     G::Edge: Debug,
 {
     let (mut graph, vertices, edges, incidences) = G::standard();
-    graph.delete_edge(edges[2].0);
+    let del = edges[2].0;
-    for i in 0..10 {
+    graph.delete_edge(del);
-        let remaining = incidences[i]
+    assert_eq!(vertices.len(), incidences.len());
-            .iter()
+    for (&v, incs) in vertices.iter().zip(&incidences) {
-            .filter(|x| x.edge != edges[2].0)
+        let remaining = incs.iter().filter(|x| x.edge != del).cloned().collect();
-            .cloned()
+        assert_vertex_incidences(&graph, v, remaining);
-            .collect();
-        assert_vertex_incidences(&graph, vertices[i], remaining);
     }
 }
 
@@ -406,14 +400,11 @@ where
     G::Edge: Debug,
 {
     let (mut graph, vertices, _, incidences) = G::standard();
-    graph.delete_vertex(vertices[2]);
+    let del = vertices[2];
-    for i in [0, 1, 3, 4, 5, 6, 7, 8, 9] {
+    graph.delete_vertex(del);
-        let remaining = incidences[i]
+    for (&v, incs) in vertices.iter().zip(&incidences).filter(|&(&u, _)| u != del) {
-            .iter()
+        let remaining = incs.iter().filter(|x| x.vertex != del).cloned().collect();
-            .filter(|x| x.vertex != vertices[2])
+        assert_vertex_incidence_cursor(&graph, v, remaining);
-            .cloned()
-            .collect();
-        assert_vertex_incidence_cursor(&graph, vertices[i], remaining);
     }
 }
 
@@ -423,14 +414,12 @@ where
     G::Edge: Debug,
 {
     let (mut graph, vertices, edges, incidences) = G::standard();
-    graph.delete_edge(edges[2].0);
+    let del = edges[2].0;
-    for i in 0..10 {
+    graph.delete_edge(del);
-        let remaining = incidences[i]
+    assert_eq!(vertices.len(), incidences.len());
-            .iter()
+    for (&v, incs) in vertices.iter().zip(&incidences) {
-            .filter(|x| x.edge != edges[2].0)
+        let remaining = incs.iter().filter(|x| x.edge != del).cloned().collect();
-            .cloned()
+        assert_vertex_incidence_cursor(&graph, v, remaining);
-            .collect();
-        assert_vertex_incidence_cursor(&graph, vertices[i], remaining);
     }
 }
 
@@ -445,26 +434,22 @@ fn assert_vertex_incidences<G: GraphTopology>(
     assert_eq!(
         graph.incidences(v).count(),
         expected.len(),
-        "unexpected incidence count for vertex {:?} after delete",
+        "unexpected incidence count for vertex {v:?} after delete"
-        v
     );
     for incidence in graph.incidences(v) {
         let pos = expected
             .iter()
-            .position(|x| *x == incidence)
+            .position(|&x| x == incidence)
             .unwrap_or_else(|| {
                 panic!(
-                    "unexpected incidence {incidence:?} of vertex {:?} from iterator after delete",
+                    "unexpected incidence {incidence:?} of vertex {v:?} from iterator after delete"
-                    v
                 )
             });
         expected.swap_remove(pos);
     }
     assert!(
         expected.is_empty(),
-        "expected incidences {:?} of vertex {:?} not matched by iterator after delete",
+        "expected incidences {expected:?} of vertex {v:?} not matched by iterator after delete"
-        expected,
-        v
     );
 }
 
@@ -480,20 +465,17 @@ fn assert_vertex_incidence_cursor<G: GraphTopology>(
     while let Some(incidence) = cursor.next(graph) {
         let pos = expected
             .iter()
-            .position(|x| *x == incidence)
+            .position(|&x| x == incidence)
             .unwrap_or_else(|| {
                 panic!(
-                    "unexpected incidence {incidence:?} of vertex {:?} from cursor after delete",
+                    "unexpected incidence {incidence:?} of vertex {v:?} from cursor after delete"
-                    v
                 )
             });
         expected.swap_remove(pos);
     }
     assert!(
         expected.is_empty(),
-        "expected incidences {:?} of vertex {:?} not matched by cursor after delete",
+        "expected incidences {expected:?} of vertex {v:?} not matched by cursor after delete"
-        expected,
-        v
     );
 }
 
@@ -508,22 +490,16 @@ fn assert_incident_edges_after_delete<G: GraphTopology>(
     assert_eq!(
         graph.incident_edges(v).count(),
         expected.len(),
-        "unexpected incident edge count for vertex {:?} after delete",
+        "unexpected incident edge count for vertex {v:?} after delete"
-        v
     );
     for e in graph.incident_edges(v) {
-        let pos = expected.iter().position(|f| *f == e).unwrap_or_else(|| {
+        let pos = expected.iter().position(|&f| f == e).unwrap_or_else(|| {
-            panic!(
+            panic!("unexpected incident edge {e:?} of vertex {v:?} after delete")
-                "unexpected incident edge {e:?} of vertex {:?} after delete",
-                v
-            )
         });
         expected.swap_remove(pos);
     }
     assert!(
         expected.is_empty(),
-        "expected incident edges {:?} of vertex {:?} not matched after delete",
+        "expected incident edges {expected:?} of vertex {v:?} not matched after delete"
-        expected,
-        v
     );
 }

src/testing/graph_topology_testing.rs

@@ -128,14 +128,10 @@ where
     G::Vertex: Debug,
 {
     let (graph, vertices, _, _) = G::standard();
-    let expected_degrees = [2, 5, 7, 2, 7, 2, 3, 3, 2, 3];
+    let expected = [2, 5, 7, 2, 7, 2, 3, 3, 2, 3];
-    for i in 0..graph.vertex_count() {
+    assert_eq!(vertices.len(), expected.len());
-        assert_eq!(
+    for (&v, &exp) in vertices.iter().zip(&expected) {
-            graph.degree(vertices[i]),
+        assert_eq!(graph.degree(v), exp, "unexpected degree of {v:?}");
-            expected_degrees[i],
-            "unexpected degree of {:?}",
-            vertices[i]
-        );
     }
 }
 
@@ -200,23 +196,18 @@ where
         vertices[9],
         vertices[3]
     );
-    for i in 0..graph.vertex_count() {
+    for (i, &v) in vertices.iter().enumerate() {
-        let exp = match i {
+        let exp = matches!(i, 1 | 2 | 4 | 5 | 6);
-            1 | 2 | 4 | 5 | 6 => true,
-            _ => false,
-        };
         assert_eq!(
-            graph.are_adjacent(vertices[2], vertices[i]),
+            graph.are_adjacent(vertices[2], v),
             exp,
-            "unexpected adjacency of {:?} and {:?}",
+            "unexpected adjacency of {:?} and {v:?}",
-            vertices[2],
+            vertices[2]
-            vertices[i]
         );
         assert_eq!(
-            graph.are_adjacent(vertices[i], vertices[2]),
+            graph.are_adjacent(v, vertices[2]),
             exp,
-            "unexpected adjacency of {:?} and {:?}",
+            "unexpected adjacency of {v:?} and {:?}",
-            vertices[i],
             vertices[2]
         );
     }
@@ -289,8 +280,7 @@ where
     assert_eq!(
         expected_adjacency.len(),
         0,
-        "expected adjacent vertices {:?} of {:?} were not matched by iterator",
+        "expected adjacent vertices {expected_adjacency:?} of {:?} were not matched by iterator",
-        expected_adjacency,
         vertices[4]
     );
 }
@@ -320,21 +310,19 @@ where
 {
     const K: usize = 3;
     let (graph, vertices, _) = G::multiple_edges::<K>();
-    for i in 0..2 {
+    for (i, &v) in vertices.iter().enumerate() {
-        let mut iter = graph.adjacent_vertices(vertices[i]);
+        let mut iter = graph.adjacent_vertices(v);
         for j in 0..K {
             assert_eq!(
                 iter.next(),
                 Some(vertices[1 - i]),
-                "unexpected adjacent vertex {j} of vertex {:?}",
+                "unexpected adjacent vertex {j} of vertex {v:?}"
-                vertices[i]
             );
         }
         assert_eq!(
             iter.next(),
             None,
-            "too many adjacent vertices of vertex {:?} from iterator",
+            "too many adjacent vertices of vertex {v:?} from iterator"
-            vertices[i]
         );
     }
 }
@@ -372,12 +360,11 @@ where
 {
     let (graph, [v0, v1], edges) = G::multiple_edges::<2>();
     assert_ne!(edges[0], edges[1], "edges should be distinct");
-    for i in 0..2 {
+    for (i, &e) in edges.iter().enumerate() {
-        let (u0, u1) = graph.incident_vertices(edges[i]);
+        let (u0, u1) = graph.incident_vertices(e);
         assert!(
             (u0 == v0 && u1 == v1) || (u0 == v1 && u1 == v0),
-            "unexpected incident vertices {u0:?} and {u1:?} for multi-edge {:?} (index {i})",
+            "unexpected incident vertices {u0:?} and {u1:?} for multi-edge {e:?} (index {i})"
-            edges[i]
         );
     }
 }
@@ -436,28 +423,23 @@ where
     G::Edge: Debug,
 {
     let (graph, vertices, _, incidences) = G::standard();
-    for i in 0..10 {
+    assert_eq!(vertices.len(), incidences.len());
+    for (&v, incs) in vertices.iter().zip(&incidences) {
         assert_eq!(
-            graph.incident_edges(vertices[i]).count(),
+            graph.incident_edges(v).count(),
-            incidences[i].len(),
+            incs.len(),
-            "unexpected incident edge count for vertex {:?}",
+            "unexpected incident edge count for vertex {v:?}"
-            vertices[i]
         );
-        let mut expected: Vec<_> = incidences[i].iter().map(|x| x.edge).collect();
+        let mut expected: Vec<_> = incs.iter().map(|x| x.edge).collect();
-        for e in graph.incident_edges(vertices[i]) {
+        for e in graph.incident_edges(v) {
-            let pos = expected.iter().position(|f| *f == e).unwrap_or_else(|| {
+            let pos = expected.iter().position(|&f| f == e).unwrap_or_else(|| {
-                panic!(
+                panic!("unexpected incident edge {e:?} of vertex {v:?} from iterator")
-                    "unexpected incident edge {e:?} of vertex {:?} from iterator",
-                    vertices[i]
-                )
             });
             expected.swap_remove(pos);
         }
         assert!(
             expected.is_empty(),
-            "expected incident edges {:?} of vertex {:?} were not matched by iterator",
+            "expected incident edges {expected:?} of vertex {v:?} were not matched by iterator"
-            expected,
-            vertices[i]
         );
     }
 }
@@ -488,19 +470,18 @@ where
 {
     const K: usize = 3;
     let (graph, vertices, edges) = G::multiple_edges::<K>();
-    for i in 0..2 {
+    for &v in &vertices {
         let mut expected = edges.to_vec();
-        for e in graph.incident_edges(vertices[i]) {
+        for e in graph.incident_edges(v) {
-            let pos = expected.iter().position(|f| *f == e).unwrap_or_else(|| {
+            let pos = expected
-                panic!("unexpected incident edge {e:?} of vertex {:?}", vertices[i])
+                .iter()
-            });
+                .position(|&f| f == e)
+                .unwrap_or_else(|| panic!("unexpected incident edge {e:?} of vertex {v:?}"));
             expected.swap_remove(pos);
         }
         assert!(
             expected.is_empty(),
-            "expected incident edges {:?} of vertex {:?} were not matched by iterator",
+            "expected incident edges {expected:?} of vertex {v:?} were not matched by iterator"
-            expected,
-            vertices[i]
         );
     }
 }
@@ -520,31 +501,26 @@ where
     G::Edge: Debug,
 {
     let (graph, vertices, _, incidences) = G::standard();
-    for i in 0..10 {
+    assert_eq!(vertices.len(), incidences.len());
+    for (&v, incs) in vertices.iter().zip(&incidences) {
         assert_eq!(
-            graph.incidences(vertices[i]).count(),
+            graph.incidences(v).count(),
-            incidences[i].len(),
+            incs.len(),
-            "unexpected incidence count for vertex {:?}",
+            "unexpected incidence count for vertex {v:?}"
-            vertices[i]
         );
-        let mut expected = incidences[i].clone();
+        let mut expected = incs.clone();
-        for incidence in graph.incidences(vertices[i]) {
+        for incidence in graph.incidences(v) {
             let pos = expected
                 .iter()
-                .position(|x| *x == incidence)
+                .position(|&x| x == incidence)
                 .unwrap_or_else(|| {
-                    panic!(
+                    panic!("unexpected incidence {incidence:?} of vertex {v:?} from iterator")
-                        "unexpected incidence {incidence:?} of vertex {:?} from iterator",
-                        vertices[i]
-                    )
                 });
             expected.swap_remove(pos);
         }
         assert!(
             expected.is_empty(),
-            "expected incidences {:?} of vertex {:?} were not matched by iterator",
+            "expected incidences {expected:?} of vertex {v:?} were not matched by iterator"
-            expected,
-            vertices[i]
         );
     }
 }
@@ -613,34 +589,28 @@ where
 {
     const K: usize = 3;
     let (graph, vertices, edges) = G::multiple_edges::<K>();
-    for i in 0..2 {
+    for (i, &v) in vertices.iter().enumerate() {
-        let mut iter = graph.incidences(vertices[i]);
+        let mut iter = graph.incidences(v);
         for j in 0..K {
             let current = iter.next().unwrap_or_else(|| {
-                panic!(
+                panic!("incidence {j} missing, expected {K} incidences for vertex {v:?}")
-                    "incidence {j} missing, expected {K} incidences for vertex {:?}",
-                    vertices[i]
-                )
             });
             assert_eq!(
                 current.vertex,
                 vertices[1 - i],
-                "unexpected adjacent vertex of vertex {:?} in incidence {j}",
+                "unexpected adjacent vertex of vertex {v:?} in incidence {j}"
-                vertices[i]
             );
             assert_eq!(
-                edges.iter().filter(|e| **e == current.edge).count(),
+                edges.iter().filter(|&&e| e == current.edge).count(),
                 1,
-                "unexpected incident edge {:?} of vertex {:?}",
+                "unexpected incident edge {:?} of vertex {v:?}",
-                current.edge,
+                current.edge
-                vertices[i],
             );
         }
         assert_eq!(
             iter.next(),
             None,
-            "too many adjacent vertices of {:?} from iterator",
+            "too many adjacent vertices of {v:?} from iterator"
-            vertices[i]
         );
     }
 }
@@ -665,26 +635,22 @@ where
     G::Edge: Debug,
 {
     let (graph, vertices, _, incidences) = G::standard();
-    for i in 0..10 {
+    assert_eq!(vertices.len(), incidences.len());
-        let mut expected = incidences[i].clone();
+    for (&v, incs) in vertices.iter().zip(&incidences) {
-        let mut cursor = graph.incidence_cursor(vertices[i]);
+        let mut expected = incs.clone();
+        let mut cursor = graph.incidence_cursor(v);
         while let Some(incidence) = cursor.next(&graph) {
             let pos = expected
                 .iter()
-                .position(|x| *x == incidence)
+                .position(|&x| x == incidence)
                 .unwrap_or_else(|| {
-                    panic!(
+                    panic!("unexpected incidence {incidence:?} of vertex {v:?} from cursor")
-                        "unexpected incidence {incidence:?} of vertex {:?} from cursor",
-                        vertices[i]
-                    )
                 });
             expected.swap_remove(pos);
         }
         assert!(
             expected.is_empty(),
-            "expected incidences {:?} of vertex {:?} were not matched by cursor",
+            "expected incidences {expected:?} of vertex {v:?} were not matched by cursor"
-            expected,
-            vertices[i]
         );
     }
 }
@@ -716,34 +682,28 @@ where
 {
     const K: usize = 3;
     let (graph, vertices, edges) = G::multiple_edges::<K>();
-    for i in 0..2 {
+    for (i, &v) in vertices.iter().enumerate() {
-        let mut cursor = graph.incidence_cursor(vertices[i]);
+        let mut cursor = graph.incidence_cursor(v);
         for j in 0..K {
             let current = cursor.next(&graph).unwrap_or_else(|| {
-                panic!(
+                panic!("incidence {j} missing, expected {K} incidences for vertex {v:?}")
-                    "incidence {j} missing, expected {K} incidences for vertex {:?}",
-                    vertices[i]
-                )
             });
             assert_eq!(
                 current.vertex,
                 vertices[1 - i],
-                "unexpected adjacent vertex of vertex {:?} in incidence {j}",
+                "unexpected adjacent vertex of vertex {v:?} in incidence {j}"
-                vertices[i]
             );
             assert_eq!(
-                edges.iter().filter(|e| **e == current.edge).count(),
+                edges.iter().filter(|&&e| e == current.edge).count(),
                 1,
-                "unexpected incident edge {:?} of vertex {:?}",
+                "unexpected incident edge {:?} of vertex {v:?}",
-                current.edge,
+                current.edge
-                vertices[i],
             );
         }
         assert_eq!(
             cursor.next(&graph),
             None,
-            "too many incidences of {:?} from cursor",
+            "too many incidences of {v:?} from cursor"
-            vertices[i]
         );
     }
 }
@@ -800,15 +760,14 @@ where
     for u in graph.vertices() {
         let mut expected: Vec<_> = graph.incidences(u).map(|x| x.edge).collect();
         for e in graph.incident_edges(u) {
-            let pos = expected.iter().position(|f| *f == e).unwrap_or_else(|| {
+            let pos = expected.iter().position(|&f| f == e).unwrap_or_else(|| {
                 panic!("incident edge {e:?} of vertex {u:?} missing from incidences")
             });
             expected.swap_remove(pos);
         }
         assert!(
             expected.is_empty(),
-            "incidence edges {:?} of vertex {u:?} not matched by incident_edges",
+            "incidence edges {expected:?} of vertex {u:?} not matched by incident_edges"
-            expected
         );
     }
 }

src/traits.rs

@@ -347,6 +347,7 @@ pub trait IncidenceCursor<G: GraphTopology + ?Sized>: Copy {
     /// assert!(c2.next(&graph).is_some());
     /// assert!(c2.next(&graph).is_none());
     /// ```
+    // TODO: Replace the above example graph with a path generator function.
     fn next(&mut self, graph: &G) -> Option<Incidence<G::Vertex, G::Edge>>;
 }
 

tests/dfs.rs

@@ -162,11 +162,10 @@ where
     G::Vertex: Debug,
 {
     let (graph, vertices, _, _) = G::standard();
-    for i in 0..10 {
+    for v in vertices {
         assert!(
-            algorithms::dfs_find(&graph, vertices[0], vertices[i]),
+            algorithms::dfs_find(&graph, vertices[0], v),
-            "vertex {:?} should be reachable from {:?}",
+            "vertex {v:?} should be reachable from {:?}",
-            vertices[i],
             vertices[0]
         );
     }
@@ -328,12 +327,8 @@ fn assert_dfs_visited<G: GraphTopology>(
 ) where
     G::Vertex: Debug,
 {
-    for i in 0..10 {
+    for &v in vertices {
-        assert!(
+        assert!(visited[v], "vertex {v:?} should be visited");
-            visited[vertices[i]],
-            "vertex {:?} should be visited",
-            vertices[i]
-        );
     }
 }
 
@@ -349,9 +344,8 @@ fn assert_dfs_predecessors<G: GraphTopology>(
         predecessors[vertices[0]], None,
         "source should have no predecessor"
     );
-    for i in 1..10 {
+    for &v in vertices.iter().skip(1) {
-        let v = vertices[i];
+        let p = predecessors[v].unwrap_or_else(|| panic!("vertex {v:?} should have a predecessor"));
-        let p = predecessors[v].expect(&format!("vertex {v:?} should have a predecessor"));
         assert!(
             visited[p],
             "predecessor {p:?} of vertex {v:?} should be visited"

tests/dijkstra.rs

@@ -6,7 +6,7 @@ use grapherity::algorithms::DijkstraResult;
 use grapherity::maps::ElementMap;
 use grapherity::testing::fixtures;
 use grapherity::testing::fixtures::MakeTestGraph;
-use grapherity::traits::{GraphTopology, Incidence};
+use grapherity::traits::GraphTopology;
 
 macro_rules! dijkstra_tests {
     ($T:ty) => {
@@ -78,21 +78,19 @@ fn dijkstra_zero_weight_loop<G: MakeTestGraph>()
 where
     G::Vertex: Debug + Hash,
 {
-    let (graph, vertices, _, weights) = make_two_edge_path_with_zero_weight_loops::<G>();
+    let (graph, vertices, weights) = make_two_edge_path_with_zero_weight_loops::<G>();
     let result = algorithms::dijkstra(&graph, vertices[0], |e| weights[e]);
     assert_single_vertex::<G>(&result, vertices[0]);
-    for i in 1..3 {
+    for (i, &v) in vertices.iter().enumerate().skip(1) {
         assert_eq!(
-            result.predecessors[vertices[i]],
+            result.predecessors[v],
             Some(vertices[i - 1]),
-            "unexpected predecessor of vertex {:?}",
+            "unexpected predecessor of vertex {v:?}"
-            vertices[i]
         );
         assert_eq!(
-            result.distances[vertices[i]],
+            result.distances[v],
             Some(i.try_into().unwrap()),
-            "unexpected distance of vertex {:?}",
+            "unexpected distance of vertex {v:?}"
-            vertices[i]
         );
     }
 }
@@ -101,7 +99,7 @@ fn dijkstra<G: MakeTestGraph>()
 where
     G::Vertex: Debug + Hash,
 {
-    let (graph, vertices, _, _, weights) = make_standard_weighted::<G>();
+    let (graph, vertices, weights) = make_standard_weighted::<G>();
     let result = algorithms::dijkstra(&graph, vertices[0], |e| weights[e]);
     assert_standard_weighted_distances_v0::<G>(&result.distances, &vertices);
     assert_standard_weighted_predecessors_v0::<G>(&result.predecessors, &vertices);
@@ -111,7 +109,7 @@ fn dijkstra_distances<G: MakeTestGraph>()
 where
     G::Vertex: Debug + Hash,
 {
-    let (graph, vertices, _, _, weights) = make_standard_weighted::<G>();
+    let (graph, vertices, weights) = make_standard_weighted::<G>();
     let distances = algorithms::dijkstra_distances(&graph, vertices[0], |e| weights[e]);
     assert_standard_weighted_distances_v0::<G>(&distances, &vertices);
 }
@@ -201,7 +199,7 @@ fn assert_disconnected<G: GraphTopology>(
 ) where
     G::Vertex: Debug,
 {
-    assert_distances_disconnected::<G>(&result.distances, &vertices);
+    assert_distances_disconnected::<G>(&result.distances, vertices);
     for &v in vertices {
         assert_eq!(
             result.predecessors[v], None,
@@ -242,12 +240,12 @@ fn assert_standard_weighted_predecessors_v0<G: GraphTopology>(
         vec![Some(vertices[7])],
         vec![Some(vertices[6])],
     ];
-    for i in 0..10 {
+    assert_eq!(vertices.len(), expected.len());
+    for (&v, exp) in vertices.iter().zip(&expected) {
         assert!(
-            expected[i].contains(&actual[vertices[i]]),
+            exp.contains(&actual[v]),
-            "unexpected predecessor {:?} of {:?}",
+            "unexpected predecessor {:?} of {v:?}",
-            actual[vertices[i]],
+            actual[v]
-            vertices[i]
         );
     }
 }
@@ -270,35 +268,30 @@ fn assert_standard_weighted_distances_v0<G: GraphTopology>(
         Some(145),
         Some(29),
     ];
-    for i in 0..10 {
+    assert_eq!(vertices.len(), expected.len());
+    for (&v, &exp) in vertices.iter().zip(&expected) {
         assert_eq!(
-            actual[vertices[i]], expected[i],
+            actual[v], exp,
-            "unexpected distance from {:?} to {:?}",
+            "unexpected distance from {:?} to {v:?}",
-            vertices[0], vertices[i]
+            vertices[0]
         );
     }
 }
 
-fn make_standard_weighted<G: MakeTestGraph>() -> (
+fn make_standard_weighted<G: MakeTestGraph>() -> (G, [G::Vertex; 10], ElementMap<G::Edge, u32>) {
-    G,
+    let (graph, vertices, edges, _) = G::standard();
-    [G::Vertex; 10],
-    [(G::Edge, G::Vertex, G::Vertex); 18],
-    [Vec<Incidence<G::Vertex, G::Edge>>; 10],
-    ElementMap<G::Edge, u32>,
-) {
-    let (graph, vertices, edges, incidences) = G::standard();
     let mut weights = graph.edge_map(99);
     for i in [1, 3, 7, 10, 12, 14, 15, 17] {
         weights[edges[i].0] = i.try_into().unwrap();
     }
-    (graph, vertices, edges, incidences, weights)
+    (graph, vertices, weights)
 }
 
 fn make_two_edge_path_with_zero_weight_loops<G: MakeTestGraph>()
--> (G, [G::Vertex; 3], [G::Edge; 4], ElementMap<G::Edge, u32>) {
+-> (G, [G::Vertex; 3], ElementMap<G::Edge, u32>) {
     let (graph, vertices, edges) = G::two_edge_path_with_loops();
     let mut weights = graph.edge_map(1);
     weights[edges[2]] = 0;
     weights[edges[3]] = 0;
-    (graph, vertices, edges, weights)
+    (graph, vertices, weights)
 }