test_dump.py

from io import StringIO
from test.test_json import PyTest, CTest

from test.support import bigmemtest, _1G

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

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

    def test_dump_skipkeys(self):
        v = {b'invalid_key': False, 'valid_key': True}
        with self.assertRaises(TypeError):
            self.json.dumps(v)

        s = self.json.dumps(v, skipkeys=True)
        o = self.json.loads(s)
        self.assertIn('valid_key', o)
        self.assertNotIn(b'invalid_key', o)

    def test_dump_skipkeys_indent_empty(self):
        v = {b'invalid_key': False}
        self.assertEqual(self.json.dumps(v, skipkeys=True, indent=4), '{}')

    def test_skipkeys_indent(self):
        v = {b'invalid_key': False, 'valid_key': True}
        self.assertEqual(self.json.dumps(v, skipkeys=True, indent=4), '{\n    "valid_key": true\n}')

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

    # Issue 16228: Crash on encoding resized list
    def test_encode_mutated(self):
        a = [object()] * 10
        def crasher(obj):
            del a[-1]
        self.assertEqual(self.dumps(a, default=crasher),
                 '[null, null, null, null, null]')

    # Issue 24094
    def test_encode_evil_dict(self):
        class D(dict):
            def keys(self):
                return L

        class X:
            def __hash__(self):
                del L[0]
                return 1337

            def __lt__(self, o):
                return 0

        L = [X() for i in range(1122)]
        d = D()
        d[1337] = "true.dat"
        self.assertEqual(self.dumps(d, sort_keys=True), '{"1337": "true.dat"}')

    def test_mutate_items_during_encode(self):
        c_make_encoder = getattr(self.json.encoder, 'c_make_encoder', None)
        if c_make_encoder is None:
            self.skipTest("c_make_encoder not available")

        cache = []

        class BadDict(dict):
            def __init__(self):
                super().__init__(real=1)

            def items(self):
                entries = [("boom", object())]
                cache.append(entries)
                return entries

        def encode_str(obj):
            if cache:
                cache.pop().clear()
            return '"x"'

        encoder = c_make_encoder(
            None, lambda o: "null",
            encode_str, None,
            ": ", ", ", False,
            False, True
        )

        try:
            encoder(BadDict(), 0)
        except (ValueError, RuntimeError):
            pass


class TestPyDump(TestDump, PyTest): pass

class TestCDump(TestDump, CTest):

    # The size requirement here is hopefully over-estimated (actual
    # memory consumption depending on implementation details, and also
    # system memory management, since this may allocate a lot of
    # small objects).

    @bigmemtest(size=_1G, memuse=1)
    def test_large_list(self, size):
        N = int(30 * 1024 * 1024 * (size / _1G))
        l = [1] * N
        encoded = self.dumps(l)
        self.assertEqual(len(encoded), N * 3)
        self.assertEqual(encoded[:1], "[")
        self.assertEqual(encoded[-2:], "1]")
        self.assertEqual(encoded[1:-2], "1, " * (N - 1))