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[EDIT] FILE: test_dump.py

import sys
from unittest import TestCase
from simplejson.compat import StringIO, long_type, b, binary_type, text_type, PY3
import simplejson as json

class MisbehavingTextSubtype(text_type):
    def __str__(self):
        return "FAIL!"

class MisbehavingBytesSubtype(binary_type):
    def decode(self, encoding=None):
        return "bad decode"
    def __str__(self):
        return "bad __str__"
    def __bytes__(self):
        return b("bad __bytes__")

def as_text_type(s):
    if PY3 and isinstance(s, bytes):
        return s.decode('ascii')
    return s

def decode_iso_8859_15(b):
    return b.decode('iso-8859-15')

class TestDump(TestCase):
    def test_dump(self):
        sio = StringIO()
        json.dump({}, sio)
        self.assertEqual(sio.getvalue(), '{}')

def test_constants(self):
        for c in [None, True, False]:
            self.assertTrue(json.loads(json.dumps(c)) is c)
            self.assertTrue(json.loads(json.dumps([c]))[0] is c)
            self.assertTrue(json.loads(json.dumps({'a': c}))['a'] is c)

def test_stringify_key(self):
        items = [(b('bytes'), 'bytes'),
                 (1.0, '1.0'),
                 (10, '10'),
                 (True, 'true'),
                 (False, 'false'),
                 (None, 'null'),
                 (long_type(100), '100')]
        for k, expect in items:
            self.assertEqual(
                json.loads(json.dumps({k: expect})),
                {expect: expect})
            self.assertEqual(
                json.loads(json.dumps({k: expect}, sort_keys=True)),
                {expect: expect})
        self.assertRaises(TypeError, json.dumps, {json: 1})
        for v in [{}, {'other': 1}, {b('derp'): 1, 'herp': 2}]:
            for sort_keys in [False, True]:
                v0 = dict(v)
                v0[json] = 1
                v1 = dict((as_text_type(key), val) for (key, val) in v.items())
                self.assertEqual(
                    json.loads(json.dumps(v0, skipkeys=True, sort_keys=sort_keys)),
                    v1)
                self.assertEqual(
                    json.loads(json.dumps({'': v0}, skipkeys=True, sort_keys=sort_keys)),
                    {'': v1})
                self.assertEqual(
                    json.loads(json.dumps([v0], skipkeys=True, sort_keys=sort_keys)),
                    [v1])

def test_dumps(self):
        self.assertEqual(json.dumps({}), '{}')

def test_encode_truefalse(self):
        self.assertEqual(json.dumps(
                 {True: False, False: True}, sort_keys=True),
                 '{"false": true, "true": false}')
        self.assertEqual(
            # load first because the keys are not sorted
            json.loads(json.dumps({'k1': {False: 5}, 'k2': {0: 5}})),
            {'k1': {'false': 5}, 'k2': {'0': 5}},
        )

self.assertEqual(
            json.dumps(
                {2: 3.0,
                 4.0: long_type(5),
                 False: 1,
                 long_type(6): True,
                 "7": 0},
                sort_keys=True),
            '{"2": 3.0, "4.0": 5, "6": true, "7": 0, "false": 1}')

def test_ordered_dict(self):
        # http://bugs.python.org/issue6105
        items = [('one', 1), ('two', 2), ('three', 3), ('four', 4), ('five', 5)]
        s = json.dumps(json.OrderedDict(items))
        self.assertEqual(
            s,
            '{"one": 1, "two": 2, "three": 3, "four": 4, "five": 5}')

def test_indent_unknown_type_acceptance(self):
        """
        A test against the regression mentioned at `github issue 29`_.

The indent parameter should accept any type which pretends to be
        an instance of int or long when it comes to being multiplied by
        strings, even if it is not actually an int or long, for
        backwards compatibility.

.. _github issue 29:
           http://github.com/simplejson/simplejson/issue/29
        """

class AwesomeInt(object):
            """An awesome reimplementation of integers"""

def __init__(self, *args, **kwargs):
                if len(args) > 0:
                    # [construct from literals, objects, etc.]
                    # ...

# Finally, if args[0] is an integer, store it
                    if isinstance(args[0], int):
                        self._int = args[0]

# [various methods]

def __mul__(self, other):
                # [various ways to multiply AwesomeInt objects]
                # ... finally, if the right-hand operand is not awesome enough,
                # try to do a normal integer multiplication
                if hasattr(self, '_int'):
                    return self._int * other
                else:
                    raise NotImplementedError("To do non-awesome things with"
                        " this object, please construct it from an integer!")

s = json.dumps([0, 1, 2], indent=AwesomeInt(3))
        self.assertEqual(s, '[\n   0,\n   1,\n   2\n]')

def test_accumulator(self):
        # the C API uses an accumulator that collects after 100,000 appends
        lst = [0] * 100000
        self.assertEqual(json.loads(json.dumps(lst)), lst)

def test_sort_keys(self):
        # https://github.com/simplejson/simplejson/issues/106
        for num_keys in range(2, 32):
            p = dict((str(x), x) for x in range(num_keys))
            sio = StringIO()
            json.dump(p, sio, sort_keys=True)
            self.assertEqual(sio.getvalue(), json.dumps(p, sort_keys=True))
            self.assertEqual(json.loads(sio.getvalue()), p)

def test_misbehaving_text_subtype(self):
        # https://github.com/simplejson/simplejson/issues/185
        text = "this is some text"
        self.assertEqual(
            json.dumps(MisbehavingTextSubtype(text)),
            json.dumps(text)
        )
        self.assertEqual(
            json.dumps([MisbehavingTextSubtype(text)]),
            json.dumps([text])
        )
        self.assertEqual(
            json.dumps({MisbehavingTextSubtype(text): 42}),
            json.dumps({text: 42})
        )

def test_misbehaving_bytes_subtype(self):
        data = b("this is some data \xe2\x82\xac")
        self.assertEqual(
            json.dumps(MisbehavingBytesSubtype(data)),
            json.dumps(data)
        )
        self.assertEqual(
            json.dumps([MisbehavingBytesSubtype(data)]),
            json.dumps([data])
        )
        self.assertEqual(
            json.dumps({MisbehavingBytesSubtype(data): 42}),
            json.dumps({data: 42})
        )

def test_bytes_toplevel(self):
        self.assertEqual(json.dumps(b('\xe2\x82\xac')), r'"\u20ac"')
        self.assertRaises(UnicodeDecodeError, json.dumps, b('\xa4'))
        self.assertEqual(json.dumps(b('\xa4'), encoding='iso-8859-1'),
                         r'"\u00a4"')
        self.assertEqual(json.dumps(b('\xa4'), encoding='iso-8859-15'),
                         r'"\u20ac"')
        if PY3:
            self.assertRaises(TypeError, json.dumps, b('\xe2\x82\xac'),
                              encoding=None)
            self.assertRaises(TypeError, json.dumps, b('\xa4'),
                              encoding=None)
            self.assertEqual(json.dumps(b('\xa4'), encoding=None,
                                        default=decode_iso_8859_15),
                            r'"\u20ac"')
        else:
            self.assertEqual(json.dumps(b('\xe2\x82\xac'), encoding=None),
                             r'"\u20ac"')
            self.assertRaises(UnicodeDecodeError, json.dumps, b('\xa4'),
                              encoding=None)
            self.assertRaises(UnicodeDecodeError, json.dumps, b('\xa4'),
                              encoding=None, default=decode_iso_8859_15)

def test_bytes_nested(self):
        self.assertEqual(json.dumps([b('\xe2\x82\xac')]), r'["\u20ac"]')
        self.assertRaises(UnicodeDecodeError, json.dumps, [b('\xa4')])
        self.assertEqual(json.dumps([b('\xa4')], encoding='iso-8859-1'),
                         r'["\u00a4"]')
        self.assertEqual(json.dumps([b('\xa4')], encoding='iso-8859-15'),
                         r'["\u20ac"]')
        if PY3:
            self.assertRaises(TypeError, json.dumps, [b('\xe2\x82\xac')],
                              encoding=None)
            self.assertRaises(TypeError, json.dumps, [b('\xa4')],
                              encoding=None)
            self.assertEqual(json.dumps([b('\xa4')], encoding=None,
                                        default=decode_iso_8859_15),
                             r'["\u20ac"]')
        else:
            self.assertEqual(json.dumps([b('\xe2\x82\xac')], encoding=None),
                             r'["\u20ac"]')
            self.assertRaises(UnicodeDecodeError, json.dumps, [b('\xa4')],
                              encoding=None)
            self.assertRaises(UnicodeDecodeError, json.dumps, [b('\xa4')],
                              encoding=None, default=decode_iso_8859_15)

def test_bytes_key(self):
        self.assertEqual(json.dumps({b('\xe2\x82\xac'): 42}), r'{"\u20ac": 42}')
        self.assertRaises(UnicodeDecodeError, json.dumps, {b('\xa4'): 42})
        self.assertEqual(json.dumps({b('\xa4'): 42}, encoding='iso-8859-1'),
                         r'{"\u00a4": 42}')
        self.assertEqual(json.dumps({b('\xa4'): 42}, encoding='iso-8859-15'),
                         r'{"\u20ac": 42}')
        if PY3:
            self.assertRaises(TypeError, json.dumps, {b('\xe2\x82\xac'): 42},
                              encoding=None)
            self.assertRaises(TypeError, json.dumps, {b('\xa4'): 42},
                              encoding=None)
            self.assertRaises(TypeError, json.dumps, {b('\xa4'): 42},
                              encoding=None, default=decode_iso_8859_15)
            self.assertEqual(json.dumps({b('\xa4'): 42}, encoding=None,
                                        skipkeys=True),
                             r'{}')
        else:
            self.assertEqual(json.dumps({b('\xe2\x82\xac'): 42}, encoding=None),
                             r'{"\u20ac": 42}')
            self.assertRaises(UnicodeDecodeError, json.dumps, {b('\xa4'): 42},
                              encoding=None)
            self.assertRaises(UnicodeDecodeError, json.dumps, {b('\xa4'): 42},
                              encoding=None, default=decode_iso_8859_15)
            self.assertRaises(UnicodeDecodeError, json.dumps, {b('\xa4'): 42},
                              encoding=None, skipkeys=True)

class TestFrozenDict(TestCase):
    """Test encoding of frozendict (CPython 3.15+ PEP 814)."""

def setUp(self):
        # Skip on Python versions without frozendict
        try:
            frozendict  # noqa: F821
        except NameError:
            if sys.version_info >= (3, 15):
                self.fail("frozendict should be available on Python 3.15+")
            self.skipTest("frozendict not available")

def test_frozendict_toplevel(self):
        self.assertEqual(
            json.dumps(frozendict(x=1, y=2), sort_keys=True),
            '{"x": 1, "y": 2}')

def test_frozendict_in_list(self):
        lst = [{'x': 1}, frozendict(y=2)]
        self.assertEqual(json.dumps(lst), '[{"x": 1}, {"y": 2}]')

def test_frozendict_nested(self):
        data = {'x': dict(a=1), 'y': frozendict(b=2)}
        self.assertEqual(
            json.dumps(data, sort_keys=True),
            '{"x": {"a": 1}, "y": {"b": 2}}')

class TestDictEncodingPaths(TestCase):
    """Verify that the PyDict_Next fast path (unsorted exact dict) and the
    iterator slow path (sorted, dict subclass, or non-dict mapping) produce
    identical output for a variety of edge cases."""

def _assert_same_output(self, data, **kwargs):
        """Encode data and verify the result round-trips correctly."""
        encoded = json.dumps(data, **kwargs)
        decoded = json.loads(encoded)
        # Keys are always strings after round-trip
        expected = json.loads(json.dumps(data, **kwargs))
        self.assertEqual(decoded, expected)
        return encoded

def test_exact_dict_unsorted(self):
        """Fast path: exact dict, sort_keys=False."""
        d = {"b": 2, "a": 1, "c": 3}
        result = json.loads(json.dumps(d))
        self.assertEqual(result, d)

def test_exact_dict_sorted(self):
        """Slow path: exact dict, sort_keys=True."""
        d = {"b": 2, "a": 1, "c": 3}
        self.assertEqual(
            json.dumps(d, sort_keys=True),
            '{"a": 1, "b": 2, "c": 3}')

def test_dict_subclass_unsorted(self):
        """Slow path: dict subclass falls back to iterator path."""
        class MyDict(dict):
            pass
        d = MyDict(b=2, a=1, c=3)
        result = json.loads(json.dumps(d))
        self.assertEqual(result, {"a": 1, "b": 2, "c": 3})

def test_dict_subclass_sorted(self):
        """Slow path: dict subclass with sort_keys=True."""
        class MyDict(dict):
            pass
        d = MyDict([("z", 26), ("a", 1), ("m", 13)])
        self.assertEqual(
            json.dumps(d, sort_keys=True),
            '{"a": 1, "m": 13, "z": 26}')

def test_non_string_keys_fast_path(self):
        """Fast path with non-string keys that get stringified."""
        d = {1: "int", 2.5: "float", True: "bool", None: "none"}
        result = json.loads(json.dumps(d))
        # All keys become strings
        for v in result.values():
            self.assertIn(v, ["int", "float", "bool", "none"])

def test_non_string_keys_sorted(self):
        """Slow path with non-string keys + sort_keys."""
        d = {1: "a", 2: "b", 3: "c"}
        self.assertEqual(
            json.dumps(d, sort_keys=True),
            '{"1": "a", "2": "b", "3": "c"}')

def test_skipkeys_fast_path(self):
        """Fast path: skipkeys drops unencodable keys."""
        d = {"ok": 1, json: "bad"}
        result = json.dumps(d, skipkeys=True)
        self.assertEqual(json.loads(result), {"ok": 1})

def test_skipkeys_slow_path(self):
        """Slow path: skipkeys + sort_keys drops unencodable keys."""
        d = {"ok": 1, json: "bad", "also_ok": 2}
        result = json.dumps(d, skipkeys=True, sort_keys=True)
        self.assertEqual(result, '{"also_ok": 2, "ok": 1}')

def test_empty_dict(self):
        """Empty dict takes the early-return path."""
        self.assertEqual(json.dumps({}), '{}')

def test_single_key(self):
        """Single-key dict."""
        self.assertEqual(json.dumps({"x": 1}), '{"x": 1}')

def test_nested_dicts(self):
        """Nested dicts exercise recursive encoding within the dict loop."""
        d = {"a": {"b": {"c": 1}}}
        self.assertEqual(
            json.dumps(d),
            '{"a": {"b": {"c": 1}}}')

def test_mixed_value_types(self):
        """All JSON value types as dict values."""
        d = {
            "str": "hello",
            "int": 42,
            "float": 3.14,
            "bool": True,
            "null": None,
            "list": [1, 2, 3],
            "dict": {"nested": True},
        }
        result = json.loads(json.dumps(d, sort_keys=True))
        self.assertEqual(result, d)

def test_key_memo_cache_hit(self):
        """Encoding a list of dicts with the same keys exercises the
        key_memo cache in encoder_encode_dict_key."""
        items = [{"name": "Alice", "age": 30},
                 {"name": "Bob", "age": 25},
                 {"name": "Carol", "age": 35}]
        result = json.loads(json.dumps(items))
        self.assertEqual(result, items)

def test_large_dict(self):
        """Large dict stresses the PyDict_Next iteration path."""
        d = {"key_%d" % i: i for i in range(1000)}
        result = json.loads(json.dumps(d))
        self.assertEqual(result, d)

class TestListEncodingPaths(TestCase):
    """Verify that the indexed fast path (exact list/tuple) and the
    iterator slow path (subclasses, other iterables) produce identical
    output."""

def test_exact_list(self):
        """Fast path: exact list iterates by index."""
        data = [1, "two", 3.0, True, None, [4, 5], {"k": "v"}]
        self.assertEqual(json.loads(json.dumps(data)), data)

def test_exact_tuple(self):
        """Fast path: exact tuple when tuple_as_array=True."""
        data = (1, "two", 3.0, True, None)
        self.assertEqual(
            json.dumps(data, tuple_as_array=True),
            '[1, "two", 3.0, true, null]')

def test_list_subclass(self):
        """Slow path: list subclass uses iterator."""
        class MyList(list):
            pass
        data = MyList([1, 2, 3])
        self.assertEqual(json.dumps(data), '[1, 2, 3]')

def test_tuple_subclass(self):
        """Slow path: tuple subclass uses iterator."""
        class MyTuple(tuple):
            pass
        data = MyTuple((1, 2, 3))
        self.assertEqual(
            json.dumps(data, tuple_as_array=True),
            '[1, 2, 3]')

def test_empty_list(self):
        self.assertEqual(json.dumps([]), '[]')

def test_empty_tuple(self):
        self.assertEqual(
            json.dumps((), tuple_as_array=True), '[]')

def test_single_element(self):
        self.assertEqual(json.dumps([42]), '[42]')

def test_nested_lists(self):
        data = [[1, 2], [3, [4, 5]]]
        self.assertEqual(json.loads(json.dumps(data)), data)

def test_large_list(self):
        """Large list stresses the indexed fast path."""
        data = list(range(1000))
        self.assertEqual(json.loads(json.dumps(data)), data)

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