Move main() code into tests and remove binary crate

src/models.rs

@@ -88,3 +88,99 @@ impl Graph {
             Some(Incidence(self.incidence_vertices.len() - 1));
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn vertex_count() {
+        let (graph, _) = make_test_graph();
+        assert_eq!(graph.vertex_count(), 10, "unexpected vertex count");
+    }
+
+    #[test]
+    fn edge_count() {
+        let (graph, _) = make_test_graph();
+        assert_eq!(graph.edge_count(), 14, "unexpected edge count");
+    }
+
+    #[test]
+    fn degrees() {
+        let (graph, vertices) = make_test_graph();
+        let expected_degrees = [1, 4, 4, 2, 4, 2, 3, 3, 2, 3];
+        for i in 0..graph.vertex_count() {
+            assert_eq!(
+                graph.degree(vertices[i]),
+                expected_degrees[i],
+                "unexpected degree of {:?}",
+                vertices[i]
+            );
+        }
+    }
+
+    #[test]
+    fn adjacencies() {
+        let (graph, vertices) = make_test_graph();
+        assert!(
+            graph.are_adjacent(vertices[0], vertices[1]),
+            "expected {:?} and {:?} to be adjacent",
+            vertices[0],
+            vertices[1]
+        );
+        assert!(
+            graph.are_adjacent(vertices[9], vertices[5]),
+            "expected {:?} and {:?} to be adjacent",
+            vertices[0],
+            vertices[5]
+        );
+        assert!(
+            !graph.are_adjacent(vertices[9], vertices[3]),
+            "unexpected adjacency of {:?} and {:?}",
+            vertices[9],
+            vertices[3]
+        );
+
+        for i in 0..graph.vertex_count() {
+            let exp = match i {
+                2 => continue,
+                1 | 4 | 5 | 6 => true,
+                _ => false,
+            };
+            assert_eq!(
+                graph.are_adjacent(vertices[2], vertices[i]),
+                exp,
+                "unexpected adjacency of {:?} and {:?}",
+                vertices[2],
+                vertices[i]
+            );
+            assert_eq!(
+                graph.are_adjacent(vertices[i], vertices[2]),
+                exp,
+                "unexpected adjacency of {:?} and {:?}",
+                vertices[i],
+                vertices[2]
+            );
+        }
+    }
+
+    fn make_test_graph() -> (Graph, [Vertex; 10]) {
+        let mut graph = Graph::new();
+        let vertices: [Vertex; 10] = core::array::from_fn(|_| graph.add_vertex());
+        graph.add_edge(vertices[0], vertices[1]);
+        graph.add_edge(vertices[1], vertices[2]);
+        graph.add_edge(vertices[1], vertices[3]);
+        graph.add_edge(vertices[1], vertices[4]);
+        graph.add_edge(vertices[2], vertices[4]);
+        graph.add_edge(vertices[2], vertices[5]);
+        graph.add_edge(vertices[2], vertices[6]);
+        graph.add_edge(vertices[3], vertices[6]);
+        graph.add_edge(vertices[4], vertices[7]);
+        graph.add_edge(vertices[4], vertices[8]);
+        graph.add_edge(vertices[5], vertices[9]);
+        graph.add_edge(vertices[6], vertices[9]);
+        graph.add_edge(vertices[7], vertices[8]);
+        graph.add_edge(vertices[7], vertices[9]);
+        (graph, vertices)
+    }
+}