Move common test helpers to fixtures module

src/testing/fixtures.rs

@@ -1,4 +1,6 @@
+use crate::maps::ElementMap;
 use crate::traits::{GraphTopology, GraphTopologyAddition, Incidence};
+use std::fmt::Debug;
 
 pub trait MakeTestGraph: GraphTopology + Sized {
     fn standard() -> (
@@ -162,3 +164,92 @@ impl<G: GraphTopologyAddition> MakeTestGraph for G {
         (graph, vertices, [e0, e1, e2, e3])
     }
 }
+
+pub fn assert_standard_unweighted_distances_v0<V, F>(actual_for: F, vertices: &[V])
+where
+    V: Debug + Copy,
+    F: Fn(V) -> Option<u32>,
+{
+    let expected = [0, 1, 2, 2, 2, 3, 3, 3, 3, 4];
+    for (i, v) in vertices.iter().enumerate() {
+        assert_eq!(
+            actual_for(*v),
+            Some(expected[i]),
+            "unexpected distance from vertex {:?} to vertex {:?}",
+            vertices[0],
+            vertices[i]
+        );
+    }
+}
+
+pub fn assert_standard_unweighted_predecessors_v0<V: Debug + Copy + PartialEq>(
+    actual: &ElementMap<V, Option<V>>,
+    vertices: &[V],
+) {
+    let expected = [
+        vec![None],
+        vec![Some(vertices[0])],
+        vec![Some(vertices[1])],
+        vec![Some(vertices[1])],
+        vec![Some(vertices[1])],
+        vec![Some(vertices[2])],
+        vec![Some(vertices[2]), Some(vertices[3])],
+        vec![Some(vertices[4])],
+        vec![Some(vertices[4])],
+        vec![Some(vertices[5]), Some(vertices[6]), Some(vertices[7])],
+    ];
+    for i in 0..10 {
+        assert!(
+            expected[i].contains(&actual[vertices[i]]),
+            "unexpected predecessor {:?} of vertex {:?}",
+            actual[vertices[i]],
+            vertices[i]
+        );
+    }
+}
+
+/// Asserts that the path given as `path_option` is a valid path in `graph`
+///
+/// Walks the path and asserts that it is `Some`, that it is empty if and only if
+/// `source == target`, that its edges are pairwise incident in the order given, and that it starts
+/// at `source` and ends at `target`.
+pub fn assert_valid_path<G: GraphTopology>(
+    graph: &G,
+    path_option: Option<Vec<G::Edge>>,
+    source: G::Vertex,
+    targets: &[G::Vertex],
+) -> Vec<G::Edge>
+where
+    G::Vertex: Debug,
+    G::Edge: Debug,
+{
+    let path = path_option.expect(&format!(
+        "path should exist between source vertex {:?} and connected targets {:?}",
+        source, targets
+    ));
+
+    if targets.contains(&source) {
+        assert!(
+            path.is_empty(),
+            "path from source to itself should be empty"
+        );
+    } else {
+        assert!(!path.is_empty(), "path should not be empty");
+        // Walks the path: tracks current vertex, confirms each edge is incident to it.
+        let mut current = source;
+        for (i, &e) in path.iter().enumerate() {
+            let (v1, v2) = graph.incident_vertices(e);
+            assert_ne!(v1, v2, "path should not contain loop edge {e:?}");
+            assert!(
+                v1 == current || v2 == current,
+                "path edge {e:?} (index {i}, vertices {v1:?} to {v2:?}) not incident to vertex {current:?}"
+            );
+            current = if v1 == current { v2 } else { v1 };
+        }
+        assert!(
+            targets.contains(&current),
+            "path should end at a target vertex ({targets:?}), but ended at {current:?}"
+        );
+    }
+    path
+}

tests/bfs.rs

@@ -1,9 +1,8 @@
 use std::fmt::Debug;
 
 use grapherity::algorithms;
-use grapherity::maps::ElementMap;
+use grapherity::testing::fixtures;
 use grapherity::testing::fixtures::MakeTestGraph;
-use grapherity::traits::GraphTopology;
 
 macro_rules! bfs_tests {
     ($T:ty) => {
@@ -96,8 +95,8 @@ where
 {
     let (graph, vertices, _, _) = G::standard();
     let result = algorithms::bfs(&graph, vertices[0]);
-    assert_bfs_distances::<G>(&result.distances, &vertices);
+    fixtures::assert_standard_unweighted_distances_v0(|v| result.distances[v], &vertices);
-    assert_bfs_predecessors::<G>(&result.predecessors, &vertices);
+    fixtures::assert_standard_unweighted_predecessors_v0(&result.predecessors, &vertices);
 }
 
 fn bfs_distances_single_vertex<G: MakeTestGraph>() {
@@ -135,7 +134,7 @@ where
 {
     let (graph, vertices, _, _) = G::standard();
     let distances = algorithms::bfs_distances(&graph, vertices[0]);
-    assert_bfs_distances::<G>(&distances, &vertices);
+    fixtures::assert_standard_unweighted_distances_v0(|v| distances[v], &vertices);
 }
 
 fn bfs_find_source<G: MakeTestGraph>() {
@@ -161,27 +160,10 @@ where
     G::Vertex: Debug,
 {
     let (graph, vertices, _, _) = G::standard();
-    let expected_distances = [
+    fixtures::assert_standard_unweighted_distances_v0(
-        Some(0),
+        |v| algorithms::bfs_find(&graph, vertices[0], v),
-        Some(1),
+        &vertices,
-        Some(2),
+    );
-        Some(2),
-        Some(2),
-        Some(3),
-        Some(3),
-        Some(3),
-        Some(3),
-        Some(4),
-    ];
-    for i in 0..10 {
-        assert_eq!(
-            algorithms::bfs_find(&graph, vertices[0], vertices[i]),
-            expected_distances[i],
-            "unexpected distance from {:?} to {:?}",
-            vertices[0],
-            vertices[i]
-        );
-    }
 }
 
 fn bfs_find_where_source_matches<G: MakeTestGraph>()
@@ -245,63 +227,3 @@ where
         vertices[8]
     );
 }
-
-fn assert_bfs_distances<G: GraphTopology>(
-    distances: &ElementMap<G::Vertex, Option<u32>>,
-    vertices: &[G::Vertex],
-) where
-    G::Vertex: Debug,
-{
-    let expected = [
-        Some(0),
-        Some(1),
-        Some(2),
-        Some(2),
-        Some(2),
-        Some(3),
-        Some(3),
-        Some(3),
-        Some(3),
-        Some(4),
-    ];
-    for i in 0..10 {
-        assert_eq!(
-            distances[vertices[i]], expected[i],
-            "unexpected distance from {:?} to {:?}",
-            vertices[0], vertices[i]
-        );
-    }
-}
-
-fn assert_bfs_predecessors<G: GraphTopology>(
-    predecessors: &ElementMap<G::Vertex, Option<G::Vertex>>,
-    vertices: &[G::Vertex],
-) where
-    G::Vertex: Debug,
-{
-    assert_eq!(
-        predecessors[vertices[0]], None,
-        "source should have no predecessor"
-    );
-    // Each non-source vertex's predecessor must be adjacent and at distance one less.
-    let expected_predecessors = [
-        vec![None],
-        vec![Some(vertices[0])],
-        vec![Some(vertices[1])],
-        vec![Some(vertices[1])],
-        vec![Some(vertices[1])],
-        vec![Some(vertices[2])],
-        vec![Some(vertices[2]), Some(vertices[3])],
-        vec![Some(vertices[4])],
-        vec![Some(vertices[4])],
-        vec![Some(vertices[5]), Some(vertices[6]), Some(vertices[7])],
-    ];
-    for i in 1..10 {
-        assert!(
-            expected_predecessors[i].contains(&predecessors[vertices[i]]),
-            "unexpected predecessor {:?} of {:?}",
-            predecessors[vertices[i]],
-            vertices[i]
-        );
-    }
-}

tests/dfs.rs

@@ -2,6 +2,7 @@ use std::fmt::Debug;
 
 use grapherity::algorithms;
 use grapherity::maps::ElementMap;
+use grapherity::testing::fixtures;
 use grapherity::testing::fixtures::MakeTestGraph;
 use grapherity::traits::GraphTopology;
 
@@ -257,12 +258,7 @@ where
     let (graph, vertices, e) = G::single_edge();
     let path = algorithms::dfs_find_path(&graph, vertices[0], vertices[1])
         .expect("path should exist between adjacent vertices");
-    assert_eq!(
+    assert_eq!(path, [e], "path should contain only the connecting edge");
-        path.len(),
-        1,
-        "unexpected path length between adjacent vertices"
-    );
-    assert_eq!(path[0], e, "path should use the connecting edge");
 }
 
 fn dfs_find_path<G: MakeTestGraph>()
@@ -271,11 +267,8 @@ where
     G::Edge: Debug,
 {
     let (graph, vertices, _, _) = G::standard();
-    let path = algorithms::dfs_find_path(&graph, vertices[0], vertices[9]).expect(&format!(
+    let path = algorithms::dfs_find_path(&graph, vertices[0], vertices[9]);
-        "path should exist between connected vertices {:?} and {:?}",
+    fixtures::assert_valid_path(&graph, path, vertices[0], &[vertices[9]]);
-        vertices[0], vertices[9]
-    ));
-    assert_valid_path(&graph, &path, vertices[0], vertices[9]);
 }
 
 fn dfs_find_path_where_source_matches<G: MakeTestGraph>()
@@ -320,13 +313,8 @@ where
     G::Edge: Debug,
 {
     let (graph, vertices, _, _) = G::standard();
-    let path = algorithms::dfs_find_path_where(&graph, vertices[0], |v| v == vertices[9]).expect(
+    let path = algorithms::dfs_find_path_where(&graph, vertices[0], |v| v == vertices[9]);
-        &format!(
+    _ = fixtures::assert_valid_path(&graph, path, vertices[0], &[vertices[9]]);
-            "path should exist between connected vertices {:?} and {:?}",
-            vertices[0], vertices[9]
-        ),
-    );
-    assert_valid_path(&graph, &path, vertices[0], vertices[9]);
 }
 
 fn assert_dfs_visited<G: GraphTopology>(
@@ -369,30 +357,3 @@ fn assert_dfs_predecessors<G: GraphTopology>(
         );
     }
 }
-
-fn assert_valid_path<G: GraphTopology>(
-    graph: &G,
-    path: &[G::Edge],
-    source: G::Vertex,
-    target: G::Vertex,
-) where
-    G::Vertex: Debug,
-    G::Edge: Debug,
-{
-    assert!(!path.is_empty(), "path should be non-empty");
-    // Walks the path: tracks current vertex, confirm each edge is incident to it.
-    let mut current = source;
-    for (i, &e) in path.iter().enumerate() {
-        let (v1, v2) = graph.incident_vertices(e);
-        assert_ne!(v1, v2, "path should not contain loop edge {e:?}");
-        assert!(
-            v1 == current || v2 == current,
-            "path edge {e:?} (idx {i}, {v1:?} to {v2:?}) not incident to vertex {current:?}"
-        );
-        current = if v1 == current { v2 } else { v1 };
-    }
-    assert_eq!(
-        current, target,
-        "path should end at target {target:?}, but ended at {current:?}"
-    );
-}

tests/dijkstra.rs

@@ -4,6 +4,7 @@ use std::hash::Hash;
 use grapherity::algorithms;
 use grapherity::algorithms::DijkstraResult;
 use grapherity::maps::ElementMap;
+use grapherity::testing::fixtures;
 use grapherity::testing::fixtures::MakeTestGraph;
 use grapherity::traits::{GraphTopology, Incidence};
 
@@ -94,18 +95,19 @@ fn dijkstra<G: MakeTestGraph>()
 where
     G::Vertex: Debug + Hash,
 {
-    let (graph, vertices, _, _, weights) = make_test_graph_weighted::<G>();
+    let (graph, vertices, _, _, weights) = make_standard_weighted::<G>();
     let result = algorithms::dijkstra(&graph, vertices[0], |e| weights[e]);
-    assert_test_graph::<G>(&result, &vertices);
+    assert_standard_weighted_distances_v0::<G>(&result.distances, &vertices);
+    assert_standard_weighted_predecessors_v0::<G>(&result.predecessors, &vertices);
 }
 
 fn dijkstra_distances<G: MakeTestGraph>()
 where
     G::Vertex: Debug + Hash,
 {
-    let (graph, vertices, _, _, weights) = make_test_graph_weighted::<G>();
+    let (graph, vertices, _, _, weights) = make_standard_weighted::<G>();
     let distances = algorithms::dijkstra_distances(&graph, vertices[0], |e| weights[e]);
-    assert_distances_test_graph::<G>(&distances, &vertices);
+    assert_standard_weighted_distances_v0::<G>(&distances, &vertices);
 }
 
 fn dijkstra_unweighted_single_vertex<G: MakeTestGraph>()
@@ -133,7 +135,8 @@ where
 {
     let (graph, vertices, _, _) = G::standard();
     let result = algorithms::dijkstra_unweighted(&graph, vertices[0]);
-    assert_unweighted_test_graph::<G>(&result, &vertices);
+    fixtures::assert_standard_unweighted_distances_v0(|v| result.distances[v], &vertices);
+    fixtures::assert_standard_unweighted_predecessors_v0(&result.predecessors, &vertices);
 }
 
 fn dijkstra_distances_unweighted_single_vertex<G: MakeTestGraph>()
@@ -161,7 +164,7 @@ where
 {
     let (graph, vertices, _, _) = G::standard();
     let distances = algorithms::dijkstra_distances_unweighted(&graph, vertices[0]);
-    assert_distances_unweighted_test_graph::<G>(&distances, &vertices);
+    fixtures::assert_standard_unweighted_distances_v0(|v| distances[v], &vertices);
 }
 
 fn assert_single_vertex<G: GraphTopology>(result: &DijkstraResult<G::Vertex>, v: G::Vertex)
@@ -213,12 +216,13 @@ fn assert_distances_disconnected<G: GraphTopology>(
     }
 }
 
-fn assert_test_graph<G: GraphTopology>(result: &DijkstraResult<G::Vertex>, vertices: &[G::Vertex])
+fn assert_standard_weighted_predecessors_v0<G: GraphTopology>(
-where
+    actual: &ElementMap<G::Vertex, Option<G::Vertex>>,
+    vertices: &[G::Vertex],
+) where
     G::Vertex: Debug,
 {
-    assert_distances_test_graph::<G>(&result.distances, &vertices);
+    let expected = [
-    let expected_predecessors_from_v0 = [
         vec![None],
         vec![Some(vertices[0])],
         vec![Some(vertices[4])],
@@ -232,21 +236,21 @@ where
     ];
     for i in 0..10 {
         assert!(
-            expected_predecessors_from_v0[i].contains(&result.predecessors[vertices[i]]),
+            expected[i].contains(&actual[vertices[i]]),
             "unexpected predecessor {:?} of {:?}",
-            result.predecessors[vertices[i]],
+            actual[vertices[i]],
             vertices[i]
         );
     }
 }
 
-fn assert_distances_test_graph<G: GraphTopology>(
+fn assert_standard_weighted_distances_v0<G: GraphTopology>(
-    distances: &ElementMap<G::Vertex, Option<u32>>,
+    actual: &ElementMap<G::Vertex, Option<u32>>,
     vertices: &[G::Vertex],
 ) where
     G::Vertex: Debug,
 {
-    let expected_distances_from_v0 = [
+    let expected = [
         Some(0),
         Some(1),
         Some(65),
@@ -260,70 +264,14 @@ fn assert_distances_test_graph<G: GraphTopology>(
     ];
     for i in 0..10 {
         assert_eq!(
-            distances[vertices[i]], expected_distances_from_v0[i],
+            actual[vertices[i]], expected[i],
             "unexpected distance from {:?} to {:?}",
             vertices[0], vertices[i]
         );
     }
 }
 
-fn assert_unweighted_test_graph<G: GraphTopology>(
+fn make_standard_weighted<G: MakeTestGraph>() -> (
-    result: &DijkstraResult<G::Vertex>,
-    vertices: &[G::Vertex],
-) where
-    G::Vertex: Debug,
-{
-    assert_distances_unweighted_test_graph::<G>(&result.distances, &vertices);
-    let expected_predecessors_from_v0 = [
-        vec![None],
-        vec![Some(vertices[0])],
-        vec![Some(vertices[1])],
-        vec![Some(vertices[1])],
-        vec![Some(vertices[1])],
-        vec![Some(vertices[2])],
-        vec![Some(vertices[2]), Some(vertices[3])],
-        vec![Some(vertices[4])],
-        vec![Some(vertices[4])],
-        vec![Some(vertices[5]), Some(vertices[6]), Some(vertices[7])],
-    ];
-    for i in 0..10 {
-        assert!(
-            expected_predecessors_from_v0[i].contains(&result.predecessors[vertices[i]]),
-            "unexpected predecessor {:?} of {:?}",
-            result.predecessors[vertices[i]],
-            vertices[i]
-        );
-    }
-}
-
-fn assert_distances_unweighted_test_graph<G: GraphTopology>(
-    distances: &ElementMap<G::Vertex, Option<u32>>,
-    vertices: &[G::Vertex],
-) where
-    G::Vertex: Debug,
-{
-    let expected_distances_from_v0 = [
-        Some(0),
-        Some(1),
-        Some(2),
-        Some(2),
-        Some(2),
-        Some(3),
-        Some(3),
-        Some(3),
-        Some(3),
-        Some(4),
-    ];
-    for i in 0..10 {
-        assert_eq!(
-            distances[vertices[i]], expected_distances_from_v0[i],
-            "unexpected distance from {:?} to {:?}",
-            vertices[0], vertices[i]
-        );
-    }
-}
-
-fn make_test_graph_weighted<G: MakeTestGraph>() -> (
     G,
     [G::Vertex; 10],
     [(G::Edge, G::Vertex, G::Vertex); 18],