fix(KDP): fixing tests

Author: piotrlaczkowski

.github/workflows/UTESTS.yml

@@ -71,7 +71,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11"]
+        python-version: ["3.10", "3.11", "3.12"]
         test-group: ["unit", "integration", "layers"]
         include:
           - python-version: "3.11"

kdp/processor.py

@@ -1126,6 +1126,15 @@ def _add_categorical_lookup(
         if feature.category_encoding == CategoryEncodingOptions.HASHING:
             return
 
+        # Handle empty vocabulary by providing a fallback
+        if not vocab:
+            logger.warning(
+                f"Empty vocabulary for categorical feature '{feature_name}'. "
+                "Using fallback vocabulary with placeholder values."
+            )
+            # Provide a minimal vocabulary with unknown/placeholder values
+            vocab = ["<UNK>"]
+
         # Default behavior if no specific preprocessing is defined
         if feature.feature_type == FeatureType.STRING_CATEGORICAL:
             preprocessor.add_processing_step(