Add Maze tests

tests/test_maze.py

@@ -0,0 +1,124 @@
+import pytest
+
+from reasoning_gym.games.maze import MazeConfig, MazeDataset, maze_dataset
+
+
+def test_maze_config_validation():
+    with pytest.raises(AssertionError):
+        cfg = MazeConfig(min_dist=0)
+        cfg.validate()
+
+    with pytest.raises(AssertionError):
+        cfg = MazeConfig(min_dist=10, max_dist=5)
+        cfg.validate()
+
+    with pytest.raises(AssertionError):
+        cfg = MazeConfig(min_grid_size=1, max_grid_size=5)
+        cfg.validate()
+
+    with pytest.raises(AssertionError):
+        cfg = MazeConfig(min_grid_size=10, max_grid_size=5)
+        cfg.validate()
+
+
+def test_maze_dataset_creation():
+    dataset_size = 22
+    cfg = MazeConfig(
+        min_dist=3,
+        max_dist=5,
+        min_grid_size=5,
+        max_grid_size=5,
+        seed=42,
+        size=dataset_size,
+    )
+
+    ds = MazeDataset(cfg)
+
+    assert len(ds) == dataset_size
+
+
+def test_maze_dataset_items():
+    ds = maze_dataset(
+        min_dist=3,
+        max_dist=5,
+        min_grid_size=5,
+        max_grid_size=5,
+        size=2,
+        seed=42,
+    )
+
+    for item in ds:
+        assert "question" in item
+        assert "answer" in item
+        assert "metadata" in item
+        meta = item["metadata"]
+        assert isinstance(meta["grid"], list)
+        assert isinstance(meta["shortest_path_length"], int)
+
+
+def test_maze_shortest_path_correctness():
+    """
+    Test that the BFS distance reported by each item is indeed correct and within the limits.
+    """
+    min_dist = 4
+    max_dist = 8
+    ds = maze_dataset(
+        min_dist=min_dist,
+        max_dist=max_dist,
+        min_grid_size=5,
+        max_grid_size=6,
+        size=3,
+        seed=99,
+    )
+
+    for item in ds:
+        reported_dist = int(item["answer"])
+        grid = item["metadata"]["grid"]  # list of strings
+
+        # Convert grid to 2D array
+        maze = [list(row) for row in grid]
+        size = len(maze)
+
+        start = None
+        goal = None
+        for r in range(size):
+            for c in range(len(maze[r])):
+                if maze[r][c] == item["metadata"]["start"]:
+                    start = (r, c)
+                elif maze[r][c] == item["metadata"]["goal"]:
+                    goal = (r, c)
+
+        assert start is not None, "Start not found!"
+        assert goal is not None, "Goal not found!"
+
+        # Now BFS to confirm the distance
+        bfs_dist = _bfs_distance(maze, start, goal, item["metadata"]["wall"])
+        assert (
+            bfs_dist == reported_dist
+        ), f"Mismatch in BFS distance: BFS found {bfs_dist}, item reported {reported_dist}.\n" f"Maze:\n" + "\n".join(
+            grid
+        )
+        assert bfs_dist <= max_dist and bfs_dist >= min_dist
+
+
+def _bfs_distance(maze, start, goal, wall_char):
+    """Utility BFS to confirm shortest path length in the test."""
+    from collections import deque
+
+    directions = [(-1, 0), (1, 0), (0, -1), (0, 1)]
+    visited = set([start])
+    queue = deque([(start[0], start[1], 0)])  # (row, col, distance)
+
+    while queue:
+        r, c, dist = queue.popleft()
+        if (r, c) == goal:
+            return dist
+
+        for dr, dc in directions:
+            nr, nc = r + dr, c + dc
+            if 0 <= nr < len(maze) and 0 <= nc < len(maze[0]):
+                if maze[nr][nc] != wall_char and (nr, nc) not in visited:
+                    visited.add((nr, nc))
+                    queue.append((nr, nc, dist + 1))
+
+    return None  # no path found