test: Add comprehensive unit tests for RushHourDataset

reasoning_gym/games/rush_hour.py

@@ -1,19 +1,19 @@
+import random
 import re
 from dataclasses import dataclass
 from typing import List, Optional, Tuple
-import random
 
 from ..data import read_data_file
 from ..factory import ProceduralDataset, register_dataset
 
-TEST_STRING = "BBoKMxDDDKMoIAALooIoJLEEooJFFNoGGoxN"
 
 @dataclass
 class RushHourConfig:
     """Configuration for Rush Hour puzzle generation"""
+
     min_moves: int = 1
     max_moves: int = 50
-    seed: Optional[int] = None 
+    seed: Optional[int] = None
     size: int = 500
 
     def validate(self) -> None:
@@ -100,10 +100,10 @@ class RushHourDataset(ProceduralDataset):
 
     def __init__(self, config: RushHourConfig):
         super().__init__(config=config, seed=config.seed, size=config.size)
-        
+
         # Load and filter puzzles from data file
         self.puzzles: List[Tuple[str, int]] = []  # (board_config, min_moves)
-        
+
         data = read_data_file("rush_18k.txt")
         for line in data.splitlines():
             if not line.strip():
@@ -112,21 +112,19 @@ class RushHourDataset(ProceduralDataset):
             if len(parts) >= 2:
                 min_moves = int(parts[0])
                 board_config = parts[1]
-                
+
                 if config.min_moves <= min_moves <= config.max_moves:
                     self.puzzles.append((board_config, min_moves))
-        
+
         if not self.puzzles:
-            raise ValueError(
-                f"No puzzles found with moves between {config.min_moves} and {config.max_moves}"
-            )
+            raise ValueError(f"No puzzles found with moves between {config.min_moves} and {config.max_moves}")
 
     def __getitem__(self, idx: int) -> dict:
         """Generate a single Rush Hour puzzle
-        
+
         Args:
             idx: Index of the item to generate
-            
+
         Returns:
             dict with keys:
                 - question: str, the formatted board with instructions
@@ -135,23 +133,23 @@ class RushHourDataset(ProceduralDataset):
         """
         # Create deterministic RNG from base seed and idx
         rng = random.Random(self.seed + idx)
-        
+
         # Randomly select a puzzle meeting our criteria
         board_config, min_moves = rng.choice(self.puzzles)
-        
+
         # Create board and get string representation
         board = Board(board_config)
         board_display = board.board_str()
-        
+
         instructions = (
             "Move the red car (AA) to the exit on the right.\n"
             "Specify moves in the format: 'F+1 K+1 M-1 C+3 H+2 ...'\n"
             "where the letter is the vehicle and +/- number is spaces to move right/left or down/up."
         )
-        
+
         return {
             "question": f"{instructions}\n\nBoard:\n{board_display}",
-            "answer": "",  # Multiple valid solutions exist
+            "answer": None,  # Multiple valid solutions exist
             "metadata": {
                 "board_config": board_config,
                 "min_moves": min_moves,
@@ -330,4 +328,3 @@ class Board:
 
 # Register the dataset
 register_dataset("rush_hour", RushHourDataset, RushHourConfig)
-