split common command line args parsing

A new function parse_args_common() that only parses
common command line options. The returned object can
be composed to parse more arguments.
As is done by parse_args().

freqtrade/main.py

@@ -405,7 +405,8 @@ def main() -> None:
     :return: None
     """
     global _CONF
-    args = parse_args(sys.argv[1:])
+    args = parse_args(sys.argv[1:],
+                      'Simple High Frequency Trading Bot for crypto currencies')
     if not args:
         exit(0)
 

freqtrade/misc.py

@@ -81,21 +81,12 @@ def throttle(func: Callable[..., Any], min_secs: float, *args, **kwargs) -> Any:
     return result
 
 
-def parse_args(args: List[str]):
+def parse_args_common(args: List[str], description: str):
     """
-    Parses given arguments and returns an argparse Namespace instance.
+    Parses given common arguments and returns them as a parsed object.
-    Returns None if a sub command has been selected and executed.
     """
     parser = argparse.ArgumentParser(
-        description='Simple High Frequency Trading Bot for crypto currencies'
+        description=description
-    )
-    parser.add_argument(
-        '-c', '--config',
-        help='specify configuration file (default: config.json)',
-        dest='config',
-        default='config.json',
-        type=str,
-        metavar='PATH',
     )
     parser.add_argument(
         '-v', '--verbose',
@@ -110,6 +101,30 @@ def parse_args(args: List[str]):
         action='version',
         version='%(prog)s {}'.format(__version__),
     )
+    parser.add_argument(
+        '-c', '--config',
+        help='specify configuration file (default: config.json)',
+        dest='config',
+        default='config.json',
+        type=str,
+        metavar='PATH',
+    )
+    return parser
+
+
+def parse_args(args: List[str], description: str):
+    """
+    Parses given arguments and returns an argparse Namespace instance.
+    Returns None if a sub command has been selected and executed.
+    """
+    parser = parse_args_common(args, description)
+    parser.add_argument(
+        '--dry-run-db',
+        help='Force dry run to use a local DB "tradesv3.dry_run.sqlite" instead of memory DB. Work only if dry_run is \
+             enabled.',  # noqa
+        action='store_true',
+        dest='dry_run_db',
+    )
     parser.add_argument(
         '--dynamic-whitelist',
         help='dynamically generate and update whitelist based on 24h BaseVolume (Default 20 currencies)',  # noqa
@@ -119,13 +134,7 @@ def parse_args(args: List[str]):
         metavar='INT',
         nargs='?',
     )
-    parser.add_argument(
+
-        '--dry-run-db',
-        help='Force dry run to use a local DB "tradesv3.dry_run.sqlite" instead of memory DB. Work only if dry_run is \
-             enabled.',  # noqa
-        action='store_true',
-        dest='dry_run_db',
-    )
     build_subcommands(parser)
     parsed_args = parser.parse_args(args)
 

freqtrade/tests/test_misc.py

@@ -39,7 +39,7 @@ def test_throttle_with_assets():
 
 
 def test_parse_args_defaults():
-    args = parse_args([])
+    args = parse_args([], '')
     assert args is not None
     assert args.config == 'config.json'
     assert args.dynamic_whitelist is None
@@ -48,46 +48,46 @@ def test_parse_args_defaults():
 
 def test_parse_args_invalid():
     with pytest.raises(SystemExit, match=r'2'):
-        parse_args(['-c'])
+        parse_args(['-c'], '')
 
 
 def test_parse_args_config():
-    args = parse_args(['-c', '/dev/null'])
+    args = parse_args(['-c', '/dev/null'], '')
     assert args is not None
     assert args.config == '/dev/null'
 
-    args = parse_args(['--config', '/dev/null'])
+    args = parse_args(['--config', '/dev/null'], '')
     assert args is not None
     assert args.config == '/dev/null'
 
 
 def test_parse_args_verbose():
-    args = parse_args(['-v'])
+    args = parse_args(['-v'], '')
     assert args is not None
     assert args.loglevel == 10
 
 
 def test_parse_args_dynamic_whitelist():
-    args = parse_args(['--dynamic-whitelist'])
+    args = parse_args(['--dynamic-whitelist'], '')
     assert args is not None
     assert args.dynamic_whitelist is 20
 
 
 def test_parse_args_dynamic_whitelist_10():
-    args = parse_args(['--dynamic-whitelist', '10'])
+    args = parse_args(['--dynamic-whitelist', '10'], '')
     assert args is not None
     assert args.dynamic_whitelist is 10
 
 
 def test_parse_args_dynamic_whitelist_invalid_values():
     with pytest.raises(SystemExit, match=r'2'):
-        parse_args(['--dynamic-whitelist', 'abc'])
+        parse_args(['--dynamic-whitelist', 'abc'], '')
 
 
 def test_parse_args_backtesting(mocker):
     backtesting_mock = mocker.patch(
         'freqtrade.optimize.backtesting.start', MagicMock())
-    args = parse_args(['backtesting'])
+    args = parse_args(['backtesting'], '')
     assert args is None
     assert backtesting_mock.call_count == 1
 
@@ -102,10 +102,10 @@ def test_parse_args_backtesting(mocker):
 
 def test_parse_args_backtesting_invalid():
     with pytest.raises(SystemExit, match=r'2'):
-        parse_args(['backtesting --ticker-interval'])
+        parse_args(['backtesting --ticker-interval'], '')
 
     with pytest.raises(SystemExit, match=r'2'):
-        parse_args(['backtesting --ticker-interval', 'abc'])
+        parse_args(['backtesting --ticker-interval', 'abc'], '')
 
 
 def test_parse_args_backtesting_custom(mocker):
@@ -116,7 +116,7 @@ def test_parse_args_backtesting_custom(mocker):
         'backtesting',
         '--live',
         '--ticker-interval', '1',
-        '--refresh-pairs-cached'])
+        '--refresh-pairs-cached'], '')
     assert args is None
     assert backtesting_mock.call_count == 1
 
@@ -133,7 +133,7 @@ def test_parse_args_backtesting_custom(mocker):
 def test_parse_args_hyperopt(mocker):
     hyperopt_mock = mocker.patch(
         'freqtrade.optimize.hyperopt.start', MagicMock())
-    args = parse_args(['hyperopt'])
+    args = parse_args(['hyperopt'], '')
     assert args is None
     assert hyperopt_mock.call_count == 1
 
@@ -147,7 +147,7 @@ def test_parse_args_hyperopt(mocker):
 def test_parse_args_hyperopt_custom(mocker):
     hyperopt_mock = mocker.patch(
         'freqtrade.optimize.hyperopt.start', MagicMock())
-    args = parse_args(['-c', 'test_conf.json', 'hyperopt', '--epochs', '20'])
+    args = parse_args(['-c', 'test_conf.json', 'hyperopt', '--epochs', '20'], '')
     assert args is None
     assert hyperopt_mock.call_count == 1