Added support for passing a tuple as expected_type to check_type()

Closes #371.

docs/versionhistory.rst

@@ -5,6 +5,9 @@ This library adheres to `Semantic Versioning 2.0 <https://semver.org/#semantic-v
 
 **UNRELEASED**
 
+- Added support for passing a tuple as ``expected_type`` to ``check_type()``, making it
+  more of a drop-in replacement for ``isinstance()``
+  (`#371 <https://github.com/agronholm/typeguard/issues/371>`_
 - Fixed regression where ``Literal`` inside a ``Union`` had quotes stripped from its
   contents, thus typically causing ``NameError`` to be raised when run
   (`#372 <https://github.com/agronholm/typeguard/issues/372>`_)

src/typeguard/_functions.py

@@ -2,7 +2,7 @@
 
 import sys
 import warnings
-from typing import Any, Callable, NoReturn, TypeVar, overload
+from typing import Any, Callable, NoReturn, TypeVar, Union, overload
 
 from . import _suppression
 from ._checkers import BINARY_MAGIC_METHODS, check_type_internal
@@ -80,7 +80,7 @@ def check_type(
     corresponding fields in :class:`TypeCheckConfiguration`.
 
     :param value: value to be checked against ``expected_type``
-    :param expected_type: a class or generic type instance
+    :param expected_type: a class or generic type instance, or a tuple of such things
     :param forward_ref_policy: see :attr:`TypeCheckConfiguration.forward_ref_policy`
     :param typecheck_fail_callback:
         see :attr`TypeCheckConfiguration.typecheck_fail_callback`
@@ -90,6 +90,9 @@ def check_type(
     :raises TypeCheckError: if there is a type mismatch
 
     """
+    if type(expected_type) is tuple:
+        expected_type = Union[expected_type]
+
     config = TypeCheckConfiguration(
         forward_ref_policy=forward_ref_policy,
         typecheck_fail_callback=typecheck_fail_callback,

tests/test_checkers.py

@@ -1080,3 +1080,11 @@ def test_imported_str_forward_ref():
     pattern = r"Skipping type check against 'Dict\[str, int\]'"
     with pytest.warns(TypeHintWarning, match=pattern):
         check_type_internal(value, "Dict[str, int]", memo)
+
+
+def test_check_against_tuple_success():
+    check_type(1, (float, Union[str, int]))
+
+
+def test_check_against_tuple_failure():
+    pytest.raises(TypeCheckError, check_type, "aa", (int, bytes))