diff --git a/reasoning_gym/arithmetic/chain_sum.py b/reasoning_gym/arithmetic/chain_sum.py
index 18519c93..e9a02d66 100644
--- a/reasoning_gym/arithmetic/chain_sum.py
+++ b/reasoning_gym/arithmetic/chain_sum.py
@@ -18,6 +18,9 @@ class ChainSumConfig:
     size: int = 500
 
     def validate(self) -> None:
+        """Validate configuration parameters"""
+        assert self.difficulty > 0, "difficulty must be positive"
+        assert self.size > 0, "size must be positive"
         """Validate configuration parameters"""
         assert self.min_terms > 0, "min_terms must be positive"
         assert self.max_terms >= self.min_terms, "max_terms must be >= min_terms"
diff --git a/tests/test_quantum_lock.py b/tests/test_quantum_lock.py
index 9c3774d5..a004afc9 100644
--- a/tests/test_quantum_lock.py
+++ b/tests/test_quantum_lock.py
@@ -1,13 +1,31 @@
-from magiccube.cube import Cube
+import pytest
 from reasoning_gym.graphs.quantum_lock import QuantumLockConfig, QuantumLockDataset
 
 
+def test_quantumlock_config_validation():
+    """Test that invalid configs raise appropriate errors"""
+    with pytest.raises(AssertionError):
+        config = QuantumLockConfig(difficulty=-1)
+        config.validate()
+
+    with pytest.raises(AssertionError):
+        config = QuantumLockConfig(size=0)
+        config.validate()
+
+
+def test_quantumlock_deterministic():
+    """Test that dataset generates same items with same seed"""
+    config = QuantumLockConfig(seed=42, size=10)
+    dataset1 = QuantumLockDataset(config)
+    dataset2 = QuantumLockDataset(config)
+
+    for i in range(len(dataset1)):
+        assert dataset1[i] == dataset2[i]
+
+
 def test_quantumlock_items():
     """Test basic properties and solution of generated items"""
-    config = QuantumLockConfig(
-        difficulty=10,
-         size=25,
-    )
+    config = QuantumLockConfig(difficulty=10, size=25)
     dataset = QuantumLockDataset(config)
 
     for item in dataset:
@@ -19,6 +37,82 @@ def test_quantumlock_items():
         # Check metadata contains required fields
         assert "solution_path" in item["metadata"]
         assert "difficulty" in item["metadata"]
+        assert "buttons" in item["metadata"]
+        assert "initial_state" in item["metadata"]
+        assert "target_value" in item["metadata"]
 
+        # Verify solution works
         assert dataset.score_answer(answer=item["metadata"]["solution_path"], entry=item) == 1.0
         assert dataset.score_answer(answer=None, entry=item) == 0.0
+
+
+def test_quantumlock_button_states():
+    """Test button state transitions and validity"""
+    config = QuantumLockConfig(difficulty=5, size=10)
+    dataset = QuantumLockDataset(config)
+
+    for item in dataset:
+        buttons = item["metadata"]["buttons"]
+        
+        # Check button properties
+        for btn in buttons:
+            assert "name" in btn
+            assert "type" in btn
+            assert "value" in btn
+            assert "active_state" in btn
+            
+            # Verify button name format
+            assert btn["name"] in ["A", "B", "C"]
+            
+            # Verify operation type
+            assert btn["type"] in ["add", "subtract", "multiply"]
+            
+            # Verify state constraints
+            assert btn["active_state"] in ["red", "green", "any"]
+
+
+def test_quantumlock_solution_validation():
+    """Test solution validation and simulation"""
+    config = QuantumLockConfig(difficulty=5, size=10)
+    dataset = QuantumLockDataset(config)
+
+    for item in dataset:
+        solution = item["metadata"]["solution_path"]
+        target = item["metadata"]["target_value"]
+        
+        # Test solution simulation
+        final_value = dataset.simulate_sequence(
+            item["metadata"],
+            solution
+        )
+        assert final_value == target
+
+        # Test invalid button sequences
+        assert dataset.simulate_sequence(
+            item["metadata"],
+            ["X", "Y", "Z"]  # Invalid buttons
+        ) == item["metadata"]["initial_value"]
+
+
+def test_quantumlock_scoring():
+    """Test score calculation for various answers"""
+    config = QuantumLockConfig(difficulty=5, size=10)
+    dataset = QuantumLockDataset(config)
+
+    for item in dataset:
+        solution = item["metadata"]["solution_path"]
+        
+        # Test correct solution
+        assert dataset.score_answer(solution, item) == 1.0
+        
+        # Test empty/None answers
+        assert dataset.score_answer(None, item) == 0.0
+        assert dataset.score_answer("", item) == 0.1
+        
+        # Test invalid buttons
+        assert dataset.score_answer("XYZ", item) == 0.1
+        
+        # Test case insensitivity
+        if solution:
+            lower_solution = "".join(solution).lower()
+            assert dataset.score_answer(lower_solution, item) == 1.0