text: #!/usr/bin/env python3
  # Copyright (c) 2017-2020 The Bitcoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  """Test various command line arguments and configuration file parameters."""
  
  import json
  
  from pathlib import Path
  
  from test_framework.test_framework import BitcoinTestFramework
  from test_framework.test_node import ErrorMatch
  from test_framework.util import assert_equal, config_file
  
  
  class SettingsTest(BitcoinTestFramework):
      def set_test_params(self):
          self.setup_clean_chain = True
          self.num_nodes = 1
          self.wallet_names = []
  
      def run_test(self):
          node, = self.nodes
          settings = Path(node.datadir, self.chain, "settings.json")
          conf = Path(node.datadir, config_file)
  
          # Assert empty settings file was created
          self.stop_node(0)
          with settings.open() as fp:
              assert_equal(json.load(fp), {})
  
          # Assert settings are parsed and logged
          with settings.open("w") as fp:
              json.dump({"string": "string", "num": 5, "bool": True, "null": None, "list": [6, 7]}, fp)
          with node.assert_debug_log(expected_msgs=[
                  'Ignoring unknown rw_settings value bool',
                  'Ignoring unknown rw_settings value list',
                  'Ignoring unknown rw_settings value null',
                  'Ignoring unknown rw_settings value num',
                  'Ignoring unknown rw_settings value string',
                  'Setting file arg: string = "string"',
                  'Setting file arg: num = 5',
                  'Setting file arg: bool = true',
                  'Setting file arg: null = null',
                  'Setting file arg: list = [6,7]',
          ]):
              self.start_node(0)
              self.stop_node(0)
  
          # Assert settings are unchanged after shutdown
          with settings.open() as fp:
              assert_equal(json.load(fp), {"string": "string", "num": 5, "bool": True, "null": None, "list": [6, 7]})
  
          # Test invalid json
          with settings.open("w") as fp:
              fp.write("invalid json")
          node.assert_start_raises_init_error(expected_msg='Unable to parse settings file', match=ErrorMatch.PARTIAL_REGEX)
  
          # Test invalid json object
          with settings.open("w") as fp:
              fp.write('"string"')
          node.assert_start_raises_init_error(expected_msg='Found non-object value "string" in settings file', match=ErrorMatch.PARTIAL_REGEX)
  
          # Test invalid settings file containing duplicate keys
          with settings.open("w") as fp:
              fp.write('{"key": 1, "key": 2}')
          node.assert_start_raises_init_error(expected_msg='Found duplicate key key in settings file', match=ErrorMatch.PARTIAL_REGEX)
  
          # Test invalid settings file is ignored with command line -nosettings
          with node.assert_debug_log(expected_msgs=['Command-line arg: settings=false']):
              self.start_node(0, extra_args=["-nosettings"])
              self.stop_node(0)
  
          # Test invalid settings file is ignored with config file -nosettings
          with conf.open('a') as conf:
              conf.write('nosettings=1\n')
          with node.assert_debug_log(expected_msgs=['Config file arg: [regtest] settings=false']):
              self.start_node(0)
              self.stop_node(0)
  
          # Test alternate settings path
          altsettings = Path(node.datadir, "altsettings.json")
          with altsettings.open("w") as fp:
              fp.write('{"key": "value"}')
          with node.assert_debug_log(expected_msgs=['Setting file arg: key = "value"']):
              self.start_node(0, extra_args=[f"-settings={altsettings}"])
              self.stop_node(0)
  
  
  if __name__ == '__main__':
      SettingsTest().main()
  