cpython/Lib/test/test_genericalias.py

"""Tests for C-implemented GenericAlias."""

import unittest
import pickle
from collections import (
    defaultdict, deque, OrderedDict, Counter, UserDict, UserList
)
from collections.abc import *
from concurrent.futures import Future
from concurrent.futures.thread import _WorkItem
from contextlib import AbstractContextManager, AbstractAsyncContextManager
from contextvars import ContextVar, Token
from dataclasses import Field
from functools import partial, partialmethod, cached_property
from mailbox import Mailbox, _PartialFile
try:
    import ctypes
except ImportError:
    ctypes = None
from difflib import SequenceMatcher
from filecmp import dircmp
from fileinput import FileInput
from itertools import chain
from http.cookies import Morsel
from multiprocessing.managers import ValueProxy
from multiprocessing.pool import ApplyResult
try:
    from multiprocessing.shared_memory import ShareableList
except ImportError:
    # multiprocessing.shared_memory is not available on e.g. Android
    ShareableList = None
from multiprocessing.queues import SimpleQueue as MPSimpleQueue
from os import DirEntry
from re import Pattern, Match
from types import GenericAlias, MappingProxyType, AsyncGeneratorType
from tempfile import TemporaryDirectory, SpooledTemporaryFile
from urllib.parse import SplitResult, ParseResult
from unittest.case import _AssertRaisesContext
from queue import Queue, SimpleQueue
from weakref import WeakSet, ReferenceType, ref
import typing

from typing import TypeVar
T = TypeVar('T')
K = TypeVar('K')
V = TypeVar('V')

class BaseTest(unittest.TestCase):
    """Test basics."""
    generic_types = [type, tuple, list, dict, set, frozenset, enumerate,
                     defaultdict, deque,
                     SequenceMatcher,
                     dircmp,
                     FileInput,
                     OrderedDict, Counter, UserDict, UserList,
                     Pattern, Match,
                     partial, partialmethod, cached_property,
                     AbstractContextManager, AbstractAsyncContextManager,
                     Awaitable, Coroutine,
                     AsyncIterable, AsyncIterator,
                     AsyncGenerator, Generator,
                     Iterable, Iterator,
                     Reversible,
                     Container, Collection,
                     Mailbox, _PartialFile,
                     ContextVar, Token,
                     Field,
                     Set, MutableSet,
                     Mapping, MutableMapping, MappingView,
                     KeysView, ItemsView, ValuesView,
                     Sequence, MutableSequence,
                     MappingProxyType, AsyncGeneratorType,
                     DirEntry,
                     chain,
                     TemporaryDirectory, SpooledTemporaryFile,
                     Queue, SimpleQueue,
                     _AssertRaisesContext,
                     SplitResult, ParseResult,
                     ValueProxy, ApplyResult,
                     WeakSet, ReferenceType, ref,
                     ShareableList, MPSimpleQueue,
                     Future, _WorkItem,
                     Morsel]
    if ctypes is not None:
        generic_types.extend((ctypes.Array, ctypes.LibraryLoader))

    def test_subscriptable(self):
        for t in self.generic_types:
            if t is None:
                continue
            tname = t.__name__
            with self.subTest(f"Testing {tname}"):
                alias = t[int]
                self.assertIs(alias.__origin__, t)
                self.assertEqual(alias.__args__, (int,))
                self.assertEqual(alias.__parameters__, ())

    def test_unsubscriptable(self):
        for t in int, str, float, Sized, Hashable:
            tname = t.__name__
            with self.subTest(f"Testing {tname}"):
                with self.assertRaises(TypeError):
                    t[int]

    def test_instantiate(self):
        for t in tuple, list, dict, set, frozenset, defaultdict, deque:
            tname = t.__name__
            with self.subTest(f"Testing {tname}"):
                alias = t[int]
                self.assertEqual(alias(), t())
                if t is dict:
                    self.assertEqual(alias(iter([('a', 1), ('b', 2)])), dict(a=1, b=2))
                    self.assertEqual(alias(a=1, b=2), dict(a=1, b=2))
                elif t is defaultdict:
                    def default():
                        return 'value'
                    a = alias(default)
                    d = defaultdict(default)
                    self.assertEqual(a['test'], d['test'])
                else:
                    self.assertEqual(alias(iter((1, 2, 3))), t((1, 2, 3)))

    def test_unbound_methods(self):
        t = list[int]
        a = t()
        t.append(a, 'foo')
        self.assertEqual(a, ['foo'])
        x = t.__getitem__(a, 0)
        self.assertEqual(x, 'foo')
        self.assertEqual(t.__len__(a), 1)

    def test_subclassing(self):
        class C(list[int]):
            pass
        self.assertEqual(C.__bases__, (list,))
        self.assertEqual(C.__class__, type)

    def test_class_methods(self):
        t = dict[int, None]
        self.assertEqual(dict.fromkeys(range(2)), {0: None, 1: None})  # This works
        self.assertEqual(t.fromkeys(range(2)), {0: None, 1: None})  # Should be equivalent

    def test_no_chaining(self):
        t = list[int]
        with self.assertRaises(TypeError):
            t[int]

    def test_generic_subclass(self):
        class MyList(list):
            pass
        t = MyList[int]
        self.assertIs(t.__origin__, MyList)
        self.assertEqual(t.__args__, (int,))
        self.assertEqual(t.__parameters__, ())

    def test_repr(self):
        class MyList(list):
            pass
        self.assertEqual(repr(list[str]), 'list[str]')
        self.assertEqual(repr(list[()]), 'list[()]')
        self.assertEqual(repr(tuple[int, ...]), 'tuple[int, ...]')
        self.assertTrue(repr(MyList[int]).endswith('.BaseTest.test_repr.<locals>.MyList[int]'))
        self.assertEqual(repr(list[str]()), '[]')  # instances should keep their normal repr

    def test_exposed_type(self):
        import types
        a = types.GenericAlias(list, int)
        self.assertEqual(str(a), 'list[int]')
        self.assertIs(a.__origin__, list)
        self.assertEqual(a.__args__, (int,))
        self.assertEqual(a.__parameters__, ())

    def test_parameters(self):
        from typing import List, Dict, Callable
        D0 = dict[str, int]
        self.assertEqual(D0.__args__, (str, int))
        self.assertEqual(D0.__parameters__, ())
        D1a = dict[str, V]
        self.assertEqual(D1a.__args__, (str, V))
        self.assertEqual(D1a.__parameters__, (V,))
        D1b = dict[K, int]
        self.assertEqual(D1b.__args__, (K, int))
        self.assertEqual(D1b.__parameters__, (K,))
        D2a = dict[K, V]
        self.assertEqual(D2a.__args__, (K, V))
        self.assertEqual(D2a.__parameters__, (K, V))
        D2b = dict[T, T]
        self.assertEqual(D2b.__args__, (T, T))
        self.assertEqual(D2b.__parameters__, (T,))
        L0 = list[str]
        self.assertEqual(L0.__args__, (str,))
        self.assertEqual(L0.__parameters__, ())
        L1 = list[T]
        self.assertEqual(L1.__args__, (T,))
        self.assertEqual(L1.__parameters__, (T,))
        L2 = list[list[T]]
        self.assertEqual(L2.__args__, (list[T],))
        self.assertEqual(L2.__parameters__, (T,))
        L3 = list[List[T]]
        self.assertEqual(L3.__args__, (List[T],))
        self.assertEqual(L3.__parameters__, (T,))
        L4a = list[Dict[K, V]]
        self.assertEqual(L4a.__args__, (Dict[K, V],))
        self.assertEqual(L4a.__parameters__, (K, V))
        L4b = list[Dict[T, int]]
        self.assertEqual(L4b.__args__, (Dict[T, int],))
        self.assertEqual(L4b.__parameters__, (T,))
        L5 = list[Callable[[K, V], K]]
        self.assertEqual(L5.__args__, (Callable[[K, V], K],))
        self.assertEqual(L5.__parameters__, (K, V))

    def test_parameter_chaining(self):
        from typing import List, Dict, Union, Callable
        self.assertEqual(list[T][int], list[int])
        self.assertEqual(dict[str, T][int], dict[str, int])
        self.assertEqual(dict[T, int][str], dict[str, int])
        self.assertEqual(dict[K, V][str, int], dict[str, int])
        self.assertEqual(dict[T, T][int], dict[int, int])

        self.assertEqual(list[list[T]][int], list[list[int]])
        self.assertEqual(list[dict[T, int]][str], list[dict[str, int]])
        self.assertEqual(list[dict[str, T]][int], list[dict[str, int]])
        self.assertEqual(list[dict[K, V]][str, int], list[dict[str, int]])
        self.assertEqual(dict[T, list[int]][str], dict[str, list[int]])

        self.assertEqual(list[List[T]][int], list[List[int]])
        self.assertEqual(list[Dict[K, V]][str, int], list[Dict[str, int]])
        self.assertEqual(list[Union[K, V]][str, int], list[Union[str, int]])
        self.assertEqual(list[Callable[[K, V], K]][str, int],
                         list[Callable[[str, int], str]])
        self.assertEqual(dict[T, List[int]][str], dict[str, List[int]])

        with self.assertRaises(TypeError):
            list[int][int]
            dict[T, int][str, int]
            dict[str, T][str, int]
            dict[T, T][str, int]

    def test_equality(self):
        self.assertEqual(list[int], list[int])
        self.assertEqual(dict[str, int], dict[str, int])
        self.assertNotEqual(dict[str, int], dict[str, str])
        self.assertNotEqual(list, list[int])
        self.assertNotEqual(list[int], list)

    def test_isinstance(self):
        self.assertTrue(isinstance([], list))
        with self.assertRaises(TypeError):
            isinstance([], list[str])

    def test_issubclass(self):
        class L(list): ...
        self.assertTrue(issubclass(L, list))
        with self.assertRaises(TypeError):
            issubclass(L, list[str])

    def test_type_generic(self):
        t = type[int]
        Test = t('Test', (), {})
        self.assertTrue(isinstance(Test, type))
        test = Test()
        self.assertEqual(t(test), Test)
        self.assertEqual(t(0), int)

    def test_type_subclass_generic(self):
        class MyType(type):
            pass
        with self.assertRaises(TypeError):
            MyType[int]

    def test_pickle(self):
        alias = GenericAlias(list, T)
        s = pickle.dumps(alias)
        loaded = pickle.loads(s)
        self.assertEqual(alias.__origin__, loaded.__origin__)
        self.assertEqual(alias.__args__, loaded.__args__)
        self.assertEqual(alias.__parameters__, loaded.__parameters__)

    def test_union(self):
        a = typing.Union[list[int], list[str]]
        self.assertEqual(a.__args__, (list[int], list[str]))
        self.assertEqual(a.__parameters__, ())

    def test_union_generic(self):
        a = typing.Union[list[T], tuple[T, ...]]
        self.assertEqual(a.__args__, (list[T], tuple[T, ...]))
        self.assertEqual(a.__parameters__, (T,))

    def test_dir(self):
        dir_of_gen_alias = set(dir(list[int]))
        self.assertTrue(dir_of_gen_alias.issuperset(dir(list)))
        for generic_alias_property in ("__origin__", "__args__", "__parameters__"):
            self.assertIn(generic_alias_property, dir_of_gen_alias)

    def test_weakref(self):
        for t in self.generic_types:
            if t is None:
                continue
            tname = t.__name__
            with self.subTest(f"Testing {tname}"):
                alias = t[int]
                self.assertEqual(ref(alias)(), alias)

    def test_no_kwargs(self):
        # bpo-42576
        with self.assertRaises(TypeError):
            GenericAlias(bad=float)

    def test_subclassing_types_genericalias(self):
        class SubClass(GenericAlias): ...
        alias = SubClass(list, int)
        class Bad(GenericAlias):
            def __new__(cls, *args, **kwargs):
                super().__new__(cls, *args, **kwargs)

        self.assertEqual(alias, list[int])
        with self.assertRaises(TypeError):
            Bad(list, int, bad=int)

    def test_abc_callable(self):
        # A separate test is needed for Callable since it uses a subclass of
        # GenericAlias.
        alias = Callable[[int, str], float]
        with self.subTest("Testing subscription"):
            self.assertIs(alias.__origin__, Callable)
            self.assertEqual(alias.__args__, (int, str, float))
            self.assertEqual(alias.__parameters__, ())

        with self.subTest("Testing instance checks"):
            self.assertIsInstance(alias, GenericAlias)

        with self.subTest("Testing weakref"):
            self.assertEqual(ref(alias)(), alias)

        with self.subTest("Testing pickling"):
            s = pickle.dumps(alias)
            loaded = pickle.loads(s)
            self.assertEqual(alias.__origin__, loaded.__origin__)
            self.assertEqual(alias.__args__, loaded.__args__)
            self.assertEqual(alias.__parameters__, loaded.__parameters__)

        with self.subTest("Testing TypeVar substitution"):
            C1 = Callable[[int, T], T]
            C2 = Callable[[K, T], V]
            C3 = Callable[..., T]
            self.assertEqual(C1[str], Callable[[int, str], str])
            self.assertEqual(C2[int, float, str], Callable[[int, float], str])
            self.assertEqual(C3[int], Callable[..., int])

            # multi chaining
            C4 = C2[int, V, str]
            self.assertEqual(repr(C4).split(".")[-1], "Callable[[int, ~V], str]")
            self.assertEqual(repr(C4[dict]).split(".")[-1], "Callable[[int, dict], str]")
            self.assertEqual(C4[dict], Callable[[int, dict], str])

        with self.subTest("Testing type erasure"):
            class C1(Callable):
                def __call__(self):
                    return None
            a = C1[[int], T]
            self.assertIs(a().__class__, C1)
            self.assertEqual(a().__orig_class__, C1[[int], T])

        # bpo-42195
        with self.subTest("Testing collections.abc.Callable's consistency "
                          "with typing.Callable"):
            c1 = typing.Callable[[int, str], dict]
            c2 = Callable[[int, str], dict]
            self.assertEqual(c1.__args__, c2.__args__)
            self.assertEqual(hash(c1.__args__), hash(c2.__args__))

        with self.subTest("Testing ParamSpec uses"):
            P = typing.ParamSpec('P')
            C1 = Callable[P, T]
            # substitution
            self.assertEqual(C1[int, str], Callable[[int], str])
            self.assertEqual(C1[[int, str], str], Callable[[int, str], str])
            self.assertEqual(repr(C1).split(".")[-1], "Callable[~P, ~T]")
            self.assertEqual(repr(C1[int, str]).split(".")[-1], "Callable[[int], str]")

            C2 = Callable[P, int]
            # special case in PEP 612 where
            # X[int, str, float] == X[[int, str, float]]
            self.assertEqual(C2[int, str, float], C2[[int, str, float]])
            self.assertEqual(repr(C2).split(".")[-1], "Callable[~P, int]")
            self.assertEqual(repr(C2[int, str]).split(".")[-1], "Callable[[int, str], int]")

        with self.subTest("Testing Concatenate uses"):
            P = typing.ParamSpec('P')
            C1 = Callable[typing.Concatenate[int, P], int]
            self.assertEqual(repr(C1), "collections.abc.Callable"
                                       "[typing.Concatenate[int, ~P], int]")

if __name__ == "__main__":
    unittest.main()