test/python/utils/test_json_writer.py

   1 # SPDX-License-Identifier: GPL-3.0-or-later
   2 #
   3 # This file is part of Nominatim. (https://nominatim.org)
   4 #
   5 # Copyright (C) 2025 by the Nominatim developer community.
   6 # For a full list of authors see the git log.
   7 """
   8 Tests for the streaming JSON writer.
   9 """
  10 import json
  11
  12 import pytest
  13
  14 from nominatim_api.utils.json_writer import JsonWriter
  15
  16
  17 @pytest.mark.parametrize("inval,outstr", [(None, 'null'),
  18                                           (True, 'true'), (False, 'false'),
  19                                           (23, '23'), (0, '0'), (-1.3, '-1.3'),
  20                                           ('g\nä', '"g\\nä"'), ('"', '"\\\""'),
  21                                           ({}, '{}'), ([], '[]')])
  22 def test_simple_value(inval, outstr):
  23     writer = JsonWriter()
  24     writer.value(inval)
  25
  26     assert writer() == outstr
  27     json.loads(writer())
  28
  29
  30 def test_empty_array():
  31     writer = JsonWriter().start_array().end_array()
  32
  33     assert writer() == '[]'
  34     json.loads(writer())
  35
  36
  37 def test_array_with_single_value():
  38     writer = JsonWriter().start_array().value(None).end_array()
  39
  40     assert writer() == '[null]'
  41     json.loads(writer())
  42
  43
  44 @pytest.mark.parametrize("invals,outstr", [((1, ), '[1]'),
  45                                            (('a', 'b'), '["a","b"]')])
  46 def test_array_with_data(invals, outstr):
  47     writer = JsonWriter()
  48
  49     writer.start_array()
  50     for ival in invals:
  51         writer.value(ival).next()
  52     writer.end_array()
  53
  54     assert writer() == outstr
  55     json.loads(writer())
  56
  57
  58 def test_empty_object():
  59     writer = JsonWriter().start_object().end_object()
  60
  61     assert writer() == '{}'
  62     json.loads(writer())
  63
  64
  65 def test_object_single_entry():
  66     writer = JsonWriter()\
  67                 .start_object()\
  68                     .key('something')\
  69                     .value(5)\
  70                 .end_object()
  71
  72     assert writer() == '{"something":5}'
  73     json.loads(writer())
  74
  75
  76 def test_object_many_values():
  77     writer = JsonWriter()\
  78                 .start_object()\
  79                     .keyval('foo', None)\
  80                     .keyval('bar', {})\
  81                     .keyval('baz', 'b\taz')\
  82                 .end_object()
  83
  84     assert writer() == '{"foo":null,"bar":{},"baz":"b\\taz"}'
  85     json.loads(writer())
  86
  87
  88 def test_object_many_values_without_none():
  89     writer = JsonWriter()\
  90                 .start_object()\
  91                     .keyval_not_none('foo', 0)\
  92                     .keyval_not_none('bar', None)\
  93                     .keyval_not_none('baz', '')\
  94                     .keyval_not_none('eve', False,
  95                                      transform=lambda v: 'yes' if v else 'no')\
  96                 .end_object()
  97
  98     assert writer() == '{"foo":0,"baz":"","eve":"no"}'
  99     json.loads(writer())
 100
 101
 102 def test_raw_output():
 103     writer = JsonWriter()\
 104                 .start_array()\
 105                     .raw('{ "nicely": "formatted here" }').next()\
 106                     .value(1)\
 107                 .end_array()
 108
 109     assert writer() == '[{ "nicely": "formatted here" },1]'