refactor: Print help and duties when no arguments are given

Issue #11: #11

Author: pawamoy

Diff for: src/duty/cli.py

@@ -262,7 +262,7 @@ def main(args: list[str] | None = None) -> int:
         return 1
 
     if not arg_lists:
-        print("> Please choose at least one duty", file=sys.stderr)
+        print_help(parser, opts, collection)
         return 1
 
     global_opts = specified_options(opts, exclude={"duties_file", "list", "help", "remainder"})

Diff for: tests/test_cli.py

@@ -15,7 +15,7 @@ def test_no_duty(capsys: pytest.CaptureFixture) -> None:
     """
     assert cli.main([]) == 1
     captured = capsys.readouterr()
-    assert "choose at least one duty" in captured.err
+    assert "Available duties" in captured.out
 
 
 def test_show_help(capsys: pytest.CaptureFixture) -> None: