add docstrings for every fixture and test methods

also add tests for missing components

tests/ahriman/application/handlers/test_handler_status.py

@@ -9,6 +9,11 @@ from ahriman.models.package import Package
 
 
 def _default_args(args: argparse.Namespace) -> argparse.Namespace:
+    """
+    default arguments for these test cases
+    :param args: command line arguments fixture
+    :return: generated arguments for these test cases
+    """
     args.ahriman = True
     args.package = []
     return args