Merge pull request #31 from cavit99/main

feat: Add Word Ladder dataset generator

tests/test_word_ladder.py

@@ -0,0 +1,147 @@
+import pytest
+
+from reasoning_gym.algorithmic.word_ladder import WordLadderConfig, WordLadderDataset
+
+
+def test_word_ladder_config_validation():
+    """Test that invalid configs raise appropriate errors"""
+    # Test min_word_length validation
+    with pytest.raises(AssertionError):
+        config = WordLadderConfig(min_word_length=2)
+        config.validate()
+
+    # Test max_word_length validation
+    with pytest.raises(AssertionError):
+        config = WordLadderConfig(max_word_length=6)
+        config.validate()
+
+    # Test word length relationship
+    with pytest.raises(AssertionError):
+        config = WordLadderConfig(min_word_length=5, max_word_length=3)
+        config.validate()
+
+    # Test min_chain_length validation
+    with pytest.raises(AssertionError):
+        config = WordLadderConfig(min_chain_length=2)
+        config.validate()
+
+    # Test chain length relationship
+    with pytest.raises(AssertionError):
+        config = WordLadderConfig(min_chain_length=5, max_chain_length=3)
+        config.validate()
+
+
+def test_word_ladder_dataset_deterministic():
+    """Test that dataset generates same items with same seed"""
+    config = WordLadderConfig(seed=42, size=10)
+    dataset1 = WordLadderDataset(config)
+    dataset2 = WordLadderDataset(config)
+
+    for i in range(len(dataset1)):
+        assert dataset1[i] == dataset2[i]
+
+
+def test_word_ladder_dataset_items():
+    """Test basic properties of generated items"""
+    config = WordLadderConfig(
+        min_word_length=3,
+        max_word_length=5,
+        min_chain_length=3,
+        max_chain_length=5,
+        size=10,
+        seed=42
+    )
+    dataset = WordLadderDataset(config)
+
+    for i in range(len(dataset)):
+        item = dataset[i]
+        # Check item structure
+        assert isinstance(item, dict)
+        assert "question" in item
+        assert "answer" in item
+        assert "metadata" in item
+
+        # Check metadata
+        metadata = item["metadata"]
+        assert "start_word" in metadata
+        assert "end_word" in metadata
+        assert "word_length" in metadata
+        assert "chain_length" in metadata
+
+        # Verify word length constraints
+        word_length = metadata["word_length"]
+        assert config.min_word_length <= word_length <= config.max_word_length
+        assert len(metadata["start_word"]) == word_length
+        assert len(metadata["end_word"]) == word_length
+
+        # Verify solution chain from answer
+        solution_chain = item["answer"].split(",")
+        
+        # Handle chain length validation based on whether it's shortest path (-1) or specified length
+        if metadata["chain_length"] == -1:
+            # For shortest path, just ensure it's a valid path (we can't predict exact length)
+            assert len(solution_chain) >= 2  # Must have at least start and end words
+        else:
+            # For specified length, ensure it matches config constraints
+            assert config.min_chain_length <= len(solution_chain) <= config.max_chain_length
+            assert len(solution_chain) == metadata["chain_length"]
+        
+        assert solution_chain[0] == metadata["start_word"]
+        assert solution_chain[-1] == metadata["end_word"]
+        assert all(len(word) == word_length for word in solution_chain)
+
+        # Verify each step differs by only one letter
+        for j in range(len(solution_chain) - 1):
+            differences = sum(1 for a, b in zip(solution_chain[j], solution_chain[j + 1]) if a != b)
+            assert differences == 1
+
+
+def test_word_ladder_differs_by_one():
+    """Test the _differs_by_one helper method"""
+    config = WordLadderConfig()
+    dataset = WordLadderDataset(config)
+
+    # Test words that differ by one letter
+    assert dataset._differs_by_one("CAT", "BAT")
+    assert dataset._differs_by_one("DOG", "LOG")
+    assert dataset._differs_by_one("WORD", "WARD")
+
+    # Test words that differ by more than one letter
+    assert not dataset._differs_by_one("CAT", "DOG")
+    assert not dataset._differs_by_one("WORD", "WAND")
+
+    # Test words of different lengths
+    assert not dataset._differs_by_one("CAT", "CATS")
+    assert not dataset._differs_by_one("DOG", "DO")
+
+    # Test identical words
+    assert not dataset._differs_by_one("CAT", "CAT")
+
+
+def test_word_ladder_find_path():
+    """Test the _find_path helper method"""
+    config = WordLadderConfig()
+    dataset = WordLadderDataset(config)
+
+    # Create a small test word set
+    word_set = {"CAT", "BAT", "BAR", "CAR"}
+
+    # Test finding valid paths
+    path1 = dataset._find_path("CAT", "BAR", word_set)
+    assert path1 is not None
+    assert path1[0] == "CAT"
+    assert path1[-1] == "BAR"
+    assert all(word in word_set for word in path1)
+
+    # Test when no path exists
+    word_set = {"CAT", "DOG"}
+    path2 = dataset._find_path("CAT", "DOG", word_set)
+    assert path2 is None
+
+    # Test path to same word
+    path3 = dataset._find_path("CAT", "CAT", word_set)
+    assert path3 == ["CAT"]
+
+
+if __name__ == "__main__":
+    pytest.main([__file__])