"""Tests for typed union exhaustiveness of ToolCallError classification."""
from typing import get_args
from dbt_mcp.errors import (
ClientToolCallError,
ServerToolCallError,
)
from dbt_mcp.errors.base import ToolCallError as BaseToolCallError
def _get_all_subclasses(cls: type) -> set[type]:
"""Recursively collect all subclasses of a class."""
result = set()
for subclass in cls.__subclasses__():
result.add(subclass)
result.update(_get_all_subclasses(subclass))
return result
class TestUnionExhaustiveness:
"""Ensure every ToolCallError subclass is classified in exactly one union."""
def test_all_subclasses_are_classified(self) -> None:
client_types = set(get_args(ClientToolCallError))
server_types = set(get_args(ServerToolCallError))
all_classified = client_types | server_types
all_subclasses = _get_all_subclasses(BaseToolCallError)
unclassified = set()
for subclass in all_subclasses:
# A subclass is classified if it is in a union OR if any of its
# parent classes (other than ToolCallError) is in a union.
classified = False
for cls in subclass.__mro__:
if cls in all_classified:
classified = True
break
if not classified:
unclassified.add(subclass)
assert unclassified == set(), (
f"Unclassified ToolCallError subclasses: {unclassified}. "
"Add them to ClientToolCallError or ServerToolCallError in errors/__init__.py."
)
def test_no_overlap_between_client_and_server(self) -> None:
client_types = set(get_args(ClientToolCallError))
server_types = set(get_args(ServerToolCallError))
overlap = client_types & server_types
assert overlap == set(), (
f"Types appear in both ClientToolCallError and ServerToolCallError: {overlap}"
)
class TestIsInstanceWorks:
"""Verify isinstance checks work with the typed unions at runtime."""
def test_isinstance_client_error(self) -> None:
for error_type in get_args(ClientToolCallError):
instance = error_type("test")
assert isinstance(instance, ClientToolCallError)
def test_isinstance_server_error(self) -> None:
for error_type in get_args(ServerToolCallError):
instance = error_type("test")
assert isinstance(instance, ServerToolCallError)
