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 contextlib import AbstractContextManager, AbstractAsyncContextManager
from re import Pattern, Match
from types import GenericAlias, MappingProxyType
import typing

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

class BaseTest(unittest.TestCase):
    """Test basics."""

    def test_subscriptable(self):
        for t in (type, tuple, list, dict, set, frozenset,
                  defaultdict, deque,
                  OrderedDict, Counter, UserDict, UserList,
                  Pattern, Match,
                  AbstractContextManager, AbstractAsyncContextManager,
                  Awaitable, Coroutine,
                  AsyncIterable, AsyncIterator,
                  AsyncGenerator, Generator,
                  Iterable, Iterator,
                  Reversible,
                  Container, Collection,
                  Callable,
                  Set, MutableSet,
                  Mapping, MutableMapping, MappingView,
                  KeysView, ItemsView, ValuesView,
                  Sequence, MutableSequence,
                  MappingProxyType,
                  ):
            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 TypeVar
        T = TypeVar('T')
        K = TypeVar('K')
        V = TypeVar('V')
        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,))

    def test_parameter_chaining(self):
        from typing import TypeVar
        T = TypeVar('T')
        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[T, T][int], dict[int, 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):
        T = typing.TypeVar('T')
        a = typing.Union[list[T], tuple[T, ...]]
        self.assertEqual(a.__args__, (list[T], tuple[T, ...]))
        self.assertEqual(a.__parameters__, (T,))


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