test(pathfinding): add tests

src/pathfinding.rs

@@ -23,8 +23,9 @@ impl Maze {
         };
 
         let heuristic = |pos: &Hex| {
+            // Manhatan distance
             let diff = *pos - to;
-            (diff.x.abs() + diff.y.abs()) as u32
+            (diff.x.abs() + diff.y.abs() + diff.z().abs()) as u32 / 2
         };
 
         astar(&from, successors, heuristic, |pos| *pos == to).map(|(path, _)| path)

tests/pathfinding.rs

@@ -1,6 +1,6 @@
 use claims::*;
 use hexlab::MazeBuilder;
-use hexx::{hex, Hex};
+use hexx::{hex, EdgeDirection, Hex};
 
 #[test]
 fn basic_path() {
@@ -14,3 +14,66 @@ fn basic_path() {
         vec![start, hex(1, 0), hex(1, 1), hex(2, 1), goal]
     );
 }
+
+#[test]
+fn path_with_walls() {
+    let mut maze = assert_ok!(MazeBuilder::new().with_seed(12345).with_radius(5).build());
+    let start = Hex::new(0, 0);
+    let goal = Hex::new(2, 0);
+
+    // Block direct path with wall
+    assert_ok!(maze.add_tile_wall(&start, EdgeDirection::FLAT_SOUTH));
+
+    // Should find alternative path or no path
+    let path = maze.find_path(start, goal);
+    if let Some(path) = path {
+        // If path exists, verify it's valid
+        assert!(path.len() > 3); // Should be longer than direct path
+        assert_eq!(path.first(), Some(&start));
+        assert_eq!(path.last(), Some(&goal));
+    }
+}
+
+#[test]
+fn path_to_self() {
+    let maze = assert_ok!(MazeBuilder::new().with_seed(12345).with_radius(5).build());
+    let pos = Hex::new(0, 0);
+
+    assert_some_eq!(maze.find_path(pos, pos), vec![pos]);
+}
+
+#[test]
+fn no_path_exists() {
+    let mut maze = assert_ok!(MazeBuilder::new().with_seed(12345).with_radius(5).build());
+    let start = Hex::new(0, 0);
+    let goal = Hex::new(2, 0);
+
+    // Surround start with walls
+    for dir in EdgeDirection::ALL_DIRECTIONS {
+        assert_ok!(maze.add_tile_wall(&start, dir));
+    }
+
+    assert_none!(maze.find_path(start, goal));
+}
+
+#[test]
+fn path_in_larger_maze() {
+    let maze = assert_ok!(MazeBuilder::new().with_seed(12345).with_radius(10).build());
+    let start = Hex::new(-5, -5);
+    let goal = Hex::new(5, 5);
+
+    let path = assert_some!(maze.find_path(start, goal));
+
+    // Basic path properties
+    assert_eq!(path.first(), Some(&start));
+    assert_eq!(path.last(), Some(&goal));
+
+    // Path should be continuous
+    for window in path.windows(2) {
+        let current = window[0];
+        let next = window[1];
+        assert!(EdgeDirection::ALL_DIRECTIONS
+            .iter()
+            .any(|&dir| current.neighbor(dir) == next));
+    }
+}