path: root/src/arrow/python/pyarrow/tests/test_json.py

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from collections import OrderedDict
import io
import itertools
import json
import string
import unittest

import numpy as np
import pytest

import pyarrow as pa
from pyarrow.json import read_json, ReadOptions, ParseOptions


def generate_col_names():
    # 'a', 'b'... 'z', then 'aa', 'ab'...
    letters = string.ascii_lowercase
    yield from letters
    for first in letters:
        for second in letters:
            yield first + second


def make_random_json(num_cols=2, num_rows=10, linesep='\r\n'):
    arr = np.random.RandomState(42).randint(0, 1000, size=(num_cols, num_rows))
    col_names = list(itertools.islice(generate_col_names(), num_cols))
    lines = []
    for row in arr.T:
        json_obj = OrderedDict([(k, int(v)) for (k, v) in zip(col_names, row)])
        lines.append(json.dumps(json_obj))
    data = linesep.join(lines).encode()
    columns = [pa.array(col, type=pa.int64()) for col in arr]
    expected = pa.Table.from_arrays(columns, col_names)
    return data, expected


def test_read_options():
    cls = ReadOptions
    opts = cls()

    assert opts.block_size > 0
    opts.block_size = 12345
    assert opts.block_size == 12345

    assert opts.use_threads is True
    opts.use_threads = False
    assert opts.use_threads is False

    opts = cls(block_size=1234, use_threads=False)
    assert opts.block_size == 1234
    assert opts.use_threads is False


def test_parse_options():
    cls = ParseOptions
    opts = cls()
    assert opts.newlines_in_values is False
    assert opts.explicit_schema is None

    opts.newlines_in_values = True
    assert opts.newlines_in_values is True

    schema = pa.schema([pa.field('foo', pa.int32())])
    opts.explicit_schema = schema
    assert opts.explicit_schema == schema

    assert opts.unexpected_field_behavior == "infer"
    for value in ["ignore", "error", "infer"]:
        opts.unexpected_field_behavior = value
        assert opts.unexpected_field_behavior == value

    with pytest.raises(ValueError):
        opts.unexpected_field_behavior = "invalid-value"


class BaseTestJSONRead:

    def read_bytes(self, b, **kwargs):
        return self.read_json(pa.py_buffer(b), **kwargs)

    def check_names(self, table, names):
        assert table.num_columns == len(names)
        assert [c.name for c in table.columns] == names

    def test_file_object(self):
        data = b'{"a": 1, "b": 2}\n'
        expected_data = {'a': [1], 'b': [2]}
        bio = io.BytesIO(data)
        table = self.read_json(bio)
        assert table.to_pydict() == expected_data
        # Text files not allowed
        sio = io.StringIO(data.decode())
        with pytest.raises(TypeError):
            self.read_json(sio)

    def test_block_sizes(self):
        rows = b'{"a": 1}\n{"a": 2}\n{"a": 3}'
        read_options = ReadOptions()
        parse_options = ParseOptions()

        for data in [rows, rows + b'\n']:
            for newlines_in_values in [False, True]:
                parse_options.newlines_in_values = newlines_in_values
                read_options.block_size = 4
                with pytest.raises(ValueError,
                                   match="try to increase block size"):
                    self.read_bytes(data, read_options=read_options,
                                    parse_options=parse_options)

                # Validate reader behavior with various block sizes.
                # There used to be bugs in this area.
                for block_size in range(9, 20):
                    read_options.block_size = block_size
                    table = self.read_bytes(data, read_options=read_options,
                                            parse_options=parse_options)
                    assert table.to_pydict() == {'a': [1, 2, 3]}

    def test_no_newline_at_end(self):
        rows = b'{"a": 1,"b": 2, "c": 3}\n{"a": 4,"b": 5, "c": 6}'
        table = self.read_bytes(rows)
        assert table.to_pydict() == {
            'a': [1, 4],
            'b': [2, 5],
            'c': [3, 6],
        }

    def test_simple_ints(self):
        # Infer integer columns
        rows = b'{"a": 1,"b": 2, "c": 3}\n{"a": 4,"b": 5, "c": 6}\n'
        table = self.read_bytes(rows)
        schema = pa.schema([('a', pa.int64()),
                            ('b', pa.int64()),
                            ('c', pa.int64())])
        assert table.schema == schema
        assert table.to_pydict() == {
            'a': [1, 4],
            'b': [2, 5],
            'c': [3, 6],
        }

    def test_simple_varied(self):
        # Infer various kinds of data
        rows = (b'{"a": 1,"b": 2, "c": "3", "d": false}\n'
                b'{"a": 4.0, "b": -5, "c": "foo", "d": true}\n')
        table = self.read_bytes(rows)
        schema = pa.schema([('a', pa.float64()),
                            ('b', pa.int64()),
                            ('c', pa.string()),
                            ('d', pa.bool_())])
        assert table.schema == schema
        assert table.to_pydict() == {
            'a': [1.0, 4.0],
            'b': [2, -5],
            'c': ["3", "foo"],
            'd': [False, True],
        }

    def test_simple_nulls(self):
        # Infer various kinds of data, with nulls
        rows = (b'{"a": 1, "b": 2, "c": null, "d": null, "e": null}\n'
                b'{"a": null, "b": -5, "c": "foo", "d": null, "e": true}\n'
                b'{"a": 4.5, "b": null, "c": "nan", "d": null,"e": false}\n')
        table = self.read_bytes(rows)
        schema = pa.schema([('a', pa.float64()),
                            ('b', pa.int64()),
                            ('c', pa.string()),
                            ('d', pa.null()),
                            ('e', pa.bool_())])
        assert table.schema == schema
        assert table.to_pydict() == {
            'a': [1.0, None, 4.5],
            'b': [2, -5, None],
            'c': [None, "foo", "nan"],
            'd': [None, None, None],
            'e': [None, True, False],
        }

    def test_empty_lists(self):
        # ARROW-10955: Infer list(null)
        rows = b'{"a": []}'
        table = self.read_bytes(rows)
        schema = pa.schema([('a', pa.list_(pa.null()))])
        assert table.schema == schema
        assert table.to_pydict() == {'a': [[]]}

    def test_empty_rows(self):
        rows = b'{}\n{}\n'
        table = self.read_bytes(rows)
        schema = pa.schema([])
        assert table.schema == schema
        assert table.num_columns == 0
        assert table.num_rows == 2

    def test_reconcile_accross_blocks(self):
        # ARROW-12065: reconciling inferred types accross blocks
        first_row = b'{                               }\n'
        read_options = ReadOptions(block_size=len(first_row))
        for next_rows, expected_pylist in [
            (b'{"a": 0}', [None, 0]),
            (b'{"a": []}', [None, []]),
            (b'{"a": []}\n{"a": [[1]]}', [None, [], [[1]]]),
            (b'{"a": {}}', [None, {}]),
            (b'{"a": {}}\n{"a": {"b": {"c": 1}}}',
             [None, {"b": None}, {"b": {"c": 1}}]),
        ]:
            table = self.read_bytes(first_row + next_rows,
                                    read_options=read_options)
            expected = {"a": expected_pylist}
            assert table.to_pydict() == expected
            # Check that the issue was exercised
            assert table.column("a").num_chunks > 1

    def test_explicit_schema_with_unexpected_behaviour(self):
        # infer by default
        rows = (b'{"foo": "bar", "num": 0}\n'
                b'{"foo": "baz", "num": 1}\n')
        schema = pa.schema([
            ('foo', pa.binary())
        ])

        opts = ParseOptions(explicit_schema=schema)
        table = self.read_bytes(rows, parse_options=opts)
        assert table.schema == pa.schema([
            ('foo', pa.binary()),
            ('num', pa.int64())
        ])
        assert table.to_pydict() == {
            'foo': [b'bar', b'baz'],
            'num': [0, 1],
        }

        # ignore the unexpected fields
        opts = ParseOptions(explicit_schema=schema,
                            unexpected_field_behavior="ignore")
        table = self.read_bytes(rows, parse_options=opts)
        assert table.schema == pa.schema([
            ('foo', pa.binary()),
        ])
        assert table.to_pydict() == {
            'foo': [b'bar', b'baz'],
        }

        # raise error
        opts = ParseOptions(explicit_schema=schema,
                            unexpected_field_behavior="error")
        with pytest.raises(pa.ArrowInvalid,
                           match="JSON parse error: unexpected field"):
            self.read_bytes(rows, parse_options=opts)

    def test_small_random_json(self):
        data, expected = make_random_json(num_cols=2, num_rows=10)
        table = self.read_bytes(data)
        assert table.schema == expected.schema
        assert table.equals(expected)
        assert table.to_pydict() == expected.to_pydict()

    def test_stress_block_sizes(self):
        # Test a number of small block sizes to stress block stitching
        data_base, expected = make_random_json(num_cols=2, num_rows=100)
        read_options = ReadOptions()
        parse_options = ParseOptions()

        for data in [data_base, data_base.rstrip(b'\r\n')]:
            for newlines_in_values in [False, True]:
                parse_options.newlines_in_values = newlines_in_values
                for block_size in [22, 23, 37]:
                    read_options.block_size = block_size
                    table = self.read_bytes(data, read_options=read_options,
                                            parse_options=parse_options)
                    assert table.schema == expected.schema
                    if not table.equals(expected):
                        # Better error output
                        assert table.to_pydict() == expected.to_pydict()


class TestSerialJSONRead(BaseTestJSONRead, unittest.TestCase):

    def read_json(self, *args, **kwargs):
        read_options = kwargs.setdefault('read_options', ReadOptions())
        read_options.use_threads = False
        table = read_json(*args, **kwargs)
        table.validate(full=True)
        return table


class TestParallelJSONRead(BaseTestJSONRead, unittest.TestCase):

    def read_json(self, *args, **kwargs):
        read_options = kwargs.setdefault('read_options', ReadOptions())
        read_options.use_threads = True
        table = read_json(*args, **kwargs)
        table.validate(full=True)
        return table