Add custom exceptions

pyproject.toml

@@ -42,5 +42,5 @@ asyncio_default_fixture_loop_scope = "function"
 extend-exclude = ["tests"]
 
 [tool.ruff.lint]
-extend-select = ["I", "D", "ERA", "UP"]
+extend-select = ["I", "D", "ERA", "UP", "FURB", "TRY", "PERF"]
 ignore = ["D203", "D213"]

src/vector_search_mcp/engine/__init__.py

@@ -28,6 +28,14 @@ from typing import Literal, overload
 from .qdrant_engine import QdrantEngine
 
 
+class UnknownEngineError(Exception):
+    """Exception raised when an unknown engine is requested."""
+
+    def __init__(self, backend: str):
+        """Initialize the exception with the unknown backend."""
+        super().__init__(f"Unknown engine type: {backend}")
+
+
 class Backend(StrEnum):
     """Enumeration of supported vector database backends.
 
@@ -96,4 +104,4 @@ def get_engine(backend: Backend):
     elif backend == Backend.COSMOS:
         raise NotImplementedError("Cosmos engine is not implemented yet")
     else:
-        raise ValueError(f"Unknown engine type: {backend}")
+        raise UnknownEngineError(backend)

src/vector_search_mcp/engine/base_engine.py

@@ -12,7 +12,7 @@ maintaining a consistent interface for the semantic search workflow.
 """
 
 from abc import ABC, abstractmethod
-from typing import Generic, TypeVar
+from typing import TypeVar
 
 from ..models import Condition, SearchRow
 
@@ -22,7 +22,7 @@ ConditionType = TypeVar("ConditionType")
 __all__ = ["BaseEngine"]
 
 
-class BaseEngine(ABC, Generic[ResponseType, ConditionType]):
+class BaseEngine[ResponseType, ConditionType](ABC):
     """Abstract base class for vector search engines.
 
     This class defines the interface that all vector search engine implementations

tests/test_engine/test_factory.py

@@ -2,7 +2,7 @@ from unittest.mock import MagicMock, patch
 
 import pytest
 
-from vector_search_mcp.engine import Backend, get_engine
+from vector_search_mcp.engine import Backend, get_engine, UnknownEngineError
 from vector_search_mcp.engine.base_engine import BaseEngine
 from vector_search_mcp.engine.qdrant_engine import QdrantEngine
 
@@ -52,7 +52,7 @@ class TestEngineFactory:
         # Create an invalid engine type (bypassing enum validation)
         invalid_type = "invalid_engine"
 
-        with pytest.raises(ValueError, match="Unknown engine type: invalid_engine"):
+        with pytest.raises(UnknownEngineError, match="Unknown engine type: invalid_engine"):
             # We need to cast to bypass type checking
             get_engine(invalid_type)  # type: ignore
 
@@ -234,22 +234,22 @@ class TestEngineFactoryErrorHandling:
 
     def test_none_backend_type(self):
         """Test get_engine with None raises appropriate error"""
-        with pytest.raises((TypeError, ValueError)):
+        with pytest.raises((TypeError, UnknownEngineError)):
             get_engine(None)  # type: ignore
 
     def test_empty_string_backend_type(self):
         """Test get_engine with empty string"""
-        with pytest.raises(ValueError, match="Unknown engine type"):
+        with pytest.raises(UnknownEngineError, match="Unknown engine type"):
             get_engine("")  # type: ignore
 
     def test_numeric_backend_type(self):
         """Test get_engine with numeric input"""
-        with pytest.raises((TypeError, ValueError)):
+        with pytest.raises((TypeError, UnknownEngineError)):
             get_engine(123)  # type: ignore
 
     def test_boolean_backend_type(self):
         """Test get_engine with boolean input"""
-        with pytest.raises((TypeError, ValueError)):
+        with pytest.raises((TypeError, UnknownEngineError)):
             get_engine(True)  # type: ignore
 
     def test_get_engine_cosmos_not_implemented(self):
@@ -273,16 +273,16 @@ class TestEngineFactoryErrorHandling:
 
     def test_case_sensitive_backend_type(self):
         """Test that backend type matching is case sensitive"""
-        with pytest.raises(ValueError, match="Unknown engine type"):
+        with pytest.raises(UnknownEngineError, match="Unknown engine type"):
             get_engine("QDRANT")  # type: ignore
 
-        with pytest.raises(ValueError, match="Unknown engine type"):
+        with pytest.raises(UnknownEngineError, match="Unknown engine type"):
             get_engine("Qdrant")  # type: ignore
 
     def test_whitespace_backend_type(self):
         """Test backend type with whitespace"""
-        with pytest.raises(ValueError, match="Unknown engine type"):
+        with pytest.raises(UnknownEngineError, match="Unknown engine type"):
             get_engine(" qdrant ")  # type: ignore
 
-        with pytest.raises(ValueError, match="Unknown engine type"):
+        with pytest.raises(UnknownEngineError, match="Unknown engine type"):
             get_engine("\tqdrant\n")  # type: ignore