test_defaultdict.py

"""Unit tests for collections.defaultdict."""

import copy
import pickle
import sys
import unittest
import warnings

from collections import defaultdict

def foobar():
    return list

class TestDefaultDict(unittest.TestCase):

    def test_basic(self):
        d1 = defaultdict()
        self.assertEqual(d1.default_factory, None)
        d1.default_factory = list
        d1[12].append(42)
        self.assertEqual(d1, {12: [42]})
        d1[12].append(24)
        self.assertEqual(d1, {12: [42, 24]})
        d1[13]
        d1[14]
        self.assertEqual(d1, {12: [42, 24], 13: [], 14: []})
        self.assertTrue(d1[12] is not d1[13] is not d1[14])
        d2 = defaultdict(list, foo=1, bar=2)
        self.assertEqual(d2.default_factory, list)
        self.assertEqual(d2, {"foo": 1, "bar": 2})
        self.assertEqual(d2["foo"], 1)
        self.assertEqual(d2["bar"], 2)
        self.assertEqual(d2[42], [])
        self.assertIn("foo", d2)
        self.assertIn("foo", d2.keys())
        self.assertIn("bar", d2)
        self.assertIn("bar", d2.keys())
        self.assertIn(42, d2)
        self.assertIn(42, d2.keys())
        self.assertNotIn(12, d2)
        self.assertNotIn(12, d2.keys())
        d2.default_factory = None
        self.assertEqual(d2.default_factory, None)
        try:
            d2[15]
        except KeyError as err:
            self.assertEqual(err.args, (15,))
        else:
            self.fail("d2[15] didn't raise KeyError")
        self.assertRaises(TypeError, defaultdict, 1)

    def test_missing(self):
        with warnings.catch_warnings(record=True, action='always') as w:
            d1 = defaultdict()
            self.assertRaises(KeyError, d1.__missing__, 42)
            d1.default_factory = list
            v1 = d1.__missing__(42)
            self.assertEqual(v1, [])
            v2 = d1.__missing__(42)
            self.assertEqual(v2, [])
            self.assertIsNot(v2, v1)
        self.assertEqual(len(w), 0 if sys._is_gil_enabled() else 3)

    def test_repr(self):
        d1 = defaultdict()
        self.assertEqual(d1.default_factory, None)
        self.assertEqual(repr(d1), "defaultdict(None, {})")
        self.assertEqual(eval(repr(d1)), d1)
        d1[11] = 41
        self.assertEqual(repr(d1), "defaultdict(None, {11: 41})")
        d2 = defaultdict(int)
        self.assertEqual(d2.default_factory, int)
        d2[12] = 42
        self.assertEqual(repr(d2), "defaultdict(<class 'int'>, {12: 42})")
        def foo(): return 43
        d3 = defaultdict(foo)
        self.assertTrue(d3.default_factory is foo)
        d3[13]
        self.assertEqual(repr(d3), "defaultdict(%s, {13: 43})" % repr(foo))

    def test_copy(self):
        d1 = defaultdict()
        d2 = d1.copy()
        self.assertEqual(type(d2), defaultdict)
        self.assertEqual(d2.default_factory, None)
        self.assertEqual(d2, {})
        d1.default_factory = list
        d3 = d1.copy()
        self.assertEqual(type(d3), defaultdict)
        self.assertEqual(d3.default_factory, list)
        self.assertEqual(d3, {})
        d1[42]
        d4 = d1.copy()
        self.assertEqual(type(d4), defaultdict)
        self.assertEqual(d4.default_factory, list)
        self.assertEqual(d4, {42: []})
        d4[12]
        self.assertEqual(d4, {42: [], 12: []})

        # Issue 6637: Copy fails for empty default dict
        d = defaultdict()
        d['a'] = 42
        e = d.copy()
        self.assertEqual(e['a'], 42)

    def test_shallow_copy(self):
        d1 = defaultdict(foobar, {1: 1})
        d2 = copy.copy(d1)
        self.assertEqual(d2.default_factory, foobar)
        self.assertEqual(d2, d1)
        d1.default_factory = list
        d2 = copy.copy(d1)
        self.assertEqual(d2.default_factory, list)
        self.assertEqual(d2, d1)

    def test_deep_copy(self):
        d1 = defaultdict(foobar, {1: [1]})
        d2 = copy.deepcopy(d1)
        self.assertEqual(d2.default_factory, foobar)
        self.assertEqual(d2, d1)
        self.assertTrue(d1[1] is not d2[1])
        d1.default_factory = list
        d2 = copy.deepcopy(d1)
        self.assertEqual(d2.default_factory, list)
        self.assertEqual(d2, d1)

    def test_keyerror_without_factory(self):
        d1 = defaultdict()
        try:
            d1[(1,)]
        except KeyError as err:
            self.assertEqual(err.args[0], (1,))
        else:
            self.fail("expected KeyError")

    def test_recursive_repr(self):
        # Issue2045: stack overflow when default_factory is a bound method
        class sub(defaultdict):
            def __init__(self):
                self.default_factory = self._factory
            def _factory(self):
                return []
        d = sub()
        self.assertRegex(repr(d),
            r"sub\(<bound method .*sub\._factory "
            r"of sub\(\.\.\., \{\}\)>, \{\}\)")

    def test_callable_arg(self):
        self.assertRaises(TypeError, defaultdict, {})

    def test_pickling(self):
        d = defaultdict(int)
        d[1]
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            s = pickle.dumps(d, proto)
            o = pickle.loads(s)
            self.assertEqual(d, o)

    def test_union(self):
        i = defaultdict(int, {1: 1, 2: 2})
        s = defaultdict(str, {0: "zero", 1: "one"})

        i_s = i | s
        self.assertIs(i_s.default_factory, int)
        self.assertDictEqual(i_s, {1: "one", 2: 2, 0: "zero"})
        self.assertEqual(list(i_s), [1, 2, 0])

        s_i = s | i
        self.assertIs(s_i.default_factory, str)
        self.assertDictEqual(s_i, {0: "zero", 1: 1, 2: 2})
        self.assertEqual(list(s_i), [0, 1, 2])

        i_ds = i | dict(s)
        self.assertIs(i_ds.default_factory, int)
        self.assertDictEqual(i_ds, {1: "one", 2: 2, 0: "zero"})
        self.assertEqual(list(i_ds), [1, 2, 0])

        ds_i = dict(s) | i
        self.assertIs(ds_i.default_factory, int)
        self.assertDictEqual(ds_i, {0: "zero", 1: 1, 2: 2})
        self.assertEqual(list(ds_i), [0, 1, 2])

        with self.assertRaises(TypeError):
            i | list(s.items())
        with self.assertRaises(TypeError):
            list(s.items()) | i

        # We inherit a fine |= from dict, so just a few sanity checks here:
        i |= list(s.items())
        self.assertIs(i.default_factory, int)
        self.assertDictEqual(i, {1: "one", 2: 2, 0: "zero"})
        self.assertEqual(list(i), [1, 2, 0])

        with self.assertRaises(TypeError):
            i |= None

    def test_reentering_getitem_method(self):
        key = "conflict_test"
        count = 0

        def default_factory():
            nonlocal count
            count += 1
            local_count = count
            if count == 1:
                test_dict[key]
            return local_count

        test_dict = defaultdict(default_factory)

        self.assertEqual(count, 0)
        self.assertEqual(test_dict[key], 1)
        self.assertEqual(count, 2)

    def test_repr_recursive_factory(self):
        # gh-145492: defaultdict.__repr__ should not cause infinite recursion
        # when the factory's __repr__ calls repr() on the defaultdict.
        class ProblematicFactory:
            def __call__(self):
                return {}
            def __repr__(self):
                repr(dd)
                return f"ProblematicFactory for {dd}"

        dd = defaultdict(ProblematicFactory())
        # Should not raise RecursionError
        r = repr(dd)
        self.assertIn("ProblematicFactory for", r)

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