feat: Add CountdownGameDataset to reasoning_gym games module

tests/test_countdown_game.py

@@ -0,0 +1,87 @@
+import pytest
+
+from reasoning_gym.games.countdown_game import CountdownGameConfig, CountdownGameDataset
+
+
+def test_countdown_game_config_validation():
+    """Test that invalid configs raise appropriate errors"""
+    with pytest.raises(AssertionError):
+        config = CountdownGameConfig(min_numbers=1)  # Too few numbers
+        config.validate()
+
+    with pytest.raises(AssertionError):
+        config = CountdownGameConfig(min_numbers=4, max_numbers=3)  # Invalid range
+        config.validate()
+
+    with pytest.raises(AssertionError):
+        config = CountdownGameConfig(operators=["^"])  # Invalid operator
+        config.validate()
+
+
+def test_countdown_game_deterministic():
+    """Test that dataset generates same items with same seed"""
+    config = CountdownGameConfig(seed=42, size=10)
+    dataset1 = CountdownGameDataset(config)
+    dataset2 = CountdownGameDataset(config)
+
+    for i in range(len(dataset1)):
+        assert dataset1[i] == dataset2[i]
+
+
+def test_countdown_game_items():
+    """Test basic properties of generated items"""
+    config = CountdownGameConfig(
+        min_numbers=3,
+        max_numbers=5,
+        min_value=1,
+        max_value=20,  # Small numbers for testing
+        min_target=10,
+        max_target=100,
+        size=50,
+        seed=42
+    )
+    dataset = CountdownGameDataset(config)
+
+    for item in dataset:
+        assert isinstance(item, dict)
+        assert "question" in item
+        assert "answer" in item
+        assert "metadata" in item
+        
+        # Check metadata contains required fields
+        assert "numbers" in item["metadata"]
+        assert "target" in item["metadata"]
+        assert "expression" in item["metadata"]
+        
+        # Verify number of source numbers is within config range
+        assert config.min_numbers <= len(item["metadata"]["numbers"]) <= config.max_numbers
+        
+        # Verify target is within config range
+        assert config.min_target <= item["metadata"]["target"] <= config.max_target
+        
+        # Verify all numbers are within config range
+        assert all(config.min_value <= n <= config.max_value for n in item["metadata"]["numbers"])
+
+
+def test_countdown_game_randomization():
+    """Test number randomization configuration"""
+    config = CountdownGameConfig(
+        min_numbers=4,
+        max_numbers=4,  # Fixed size for testing
+        randomize_numbers=False,
+        size=10,
+        seed=42
+    )
+    
+    # Without randomization, numbers should appear in same order
+    dataset = CountdownGameDataset(config)
+    first_item = dataset[0]
+    expr_nums = [int(n) for n in first_item["metadata"]["expression"].replace("(","").replace(")","").split(" ") if n.isdigit()]
+    assert expr_nums == first_item["metadata"]["numbers"]
+    
+    # With randomization, numbers might appear in different order
+    config.randomize_numbers = True
+    dataset = CountdownGameDataset(config)
+    first_item = dataset[0]
+    expr_nums = [int(n) for n in first_item["metadata"]["expression"].replace("(","").replace(")","").split(" ") if n.isdigit()]
+    assert sorted(expr_nums) == sorted(first_item["metadata"]["numbers"])