Merge #16234: test: Add test for unknown args

fa7dd88 test: Add test for unknown args (MarcoFalke)

Pull request description:

  Currently uncovered.

  Further reading:

  * https://marcofalke.github.io/btc_cov/total.coverage/src/util/system.cpp.gcov.html
  *  Fail on unknown config file options #15021

ACKs for commit fa7dd8:
  promag:
    ACK fa7dd88, tests looks good to me.
  hebasto:
    ACK fa7dd88, I have tested the code.

Tree-SHA512: 86ab370ce8e85925f945a52e81457b5678d71bbabcef01205a97782b780003f363552e0bad1ff678bccc784f82c6b511c3b88de3f8f25f62b0b713c387950564

Author: MarcoFalke

test/functional/feature_config_args.py

@@ -21,6 +21,16 @@ def test_config_file_parser(self):
         with open(os.path.join(self.nodes[0].datadir, 'bitcoin.conf'), 'a', encoding='utf-8') as conf:
             conf.write('includeconf={}\n'.format(inc_conf_file_path))
 
+        self.nodes[0].assert_start_raises_init_error(
+            expected_msg='Error parsing command line arguments: Invalid parameter -dash_cli',
+            extra_args=['-dash_cli=1'],
+        )
+        with open(inc_conf_file_path, 'w', encoding='utf-8') as conf:
+            conf.write('dash_conf=1\n')
+        with self.nodes[0].assert_debug_log(expected_msgs=['Ignoring unknown configuration value dash_conf']):
+            self.start_node(0)
+        self.stop_node(0)
+
         with open(inc_conf_file_path, 'w', encoding='utf-8') as conf:
             conf.write('-dash=1\n')
         self.nodes[0].assert_start_raises_init_error(expected_msg='Error reading configuration file: parse error on line 1: -dash=1, options in configuration file must be specified without leading -')