Move test without command to test_main

tests/test_main.py

@@ -11,10 +11,16 @@ from freqtrade.freqtradebot import FreqtradeBot
 from freqtrade.main import main
 from freqtrade.state import State
 from freqtrade.worker import Worker
-from tests.conftest import (log_has, patch_exchange,
+from tests.conftest import (log_has, log_has_re, patch_exchange,
                             patched_configuration_load_config_file)
 
 
+def test_parse_args_None(caplog) -> None:
+    with pytest.raises(SystemExit):
+        main([])
+    assert log_has_re(r"Usage of freqtrade requires a subcommand\.", caplog)
+
+
 def test_parse_args_backtesting(mocker) -> None:
     """
     Test that main() can start backtesting and also ensure we can pass some specific arguments