ensure_type: a method to cast a type and check the type at runtime

Signed-off-by: Gaëtan Lehmann <[email protected]>

Author: glehmann

lib/common.py

@@ -7,7 +7,7 @@
 import time
 import traceback
 from enum import Enum
-from typing import Dict, Literal, Optional, overload, TYPE_CHECKING, Union
+from typing import Any, Dict, Literal, Optional, Type, TypeVar, overload, TYPE_CHECKING, Union
 from uuid import UUID
 
 import pytest
@@ -67,6 +67,14 @@ def expand_scope_relative_nodeid(scoped_nodeid, scope, ref_nodeid):
     logging.debug("scope: %r base: %r relative: %r", scope, base, scoped_nodeid)
     return "::".join(itertools.chain(base, (scoped_nodeid,)))
 
+T = TypeVar("T")
+
+def ensure_type(typ: Type[T], value: Any) -> T:
+    """Converts a value to the specified type. Also performs a runtime check."""
+    if not isinstance(value, typ):
+        raise TypeError(f"'{type(value).__name__}' object is not of the expected type '{typ.__name__}'")
+    return value
+
 def callable_marker(value, request):
     """
     Process value optionally generated by fixture-dependent callable.