nixos/test-driver: apply ruff fixes & suggestions

nixos/lib/test-driver/extract-docstrings.py

···
     ]
     function_definitions.sort(key=lambda x: x.name)
 
-    for f in function_definitions:
-        docstr = ast.get_docstring(f)
+    for function in function_definitions:
+        docstr = ast.get_docstring(function)
         if docstr is not None:
-            args = ", ".join(a.arg for a in f.args.args[1:])
+            args = ", ".join(a.arg for a in function.args.args[1:])
             args = f"({args})"
 
-            docstr = "\n".join(f"    {l}" for l in docstr.strip().splitlines())
+            docstr = "\n".join(f"    {line}" for line in docstr.strip().splitlines())
 
-            print(f"{f.name}{args}\n\n:{docstr[1:]}\n")
+            print(f"{function.name}{args}\n\n:{docstr[1:]}\n")
 
 
 if __name__ == "__main__":

nixos/lib/test-driver/test_driver/__init__.py

···
-from pathlib import Path
 import argparse
-import ptpython.repl
 import os
 import time
+from pathlib import Path
 
+import ptpython.repl
+
+from test_driver.driver import Driver
 from test_driver.logger import rootlog
-from test_driver.driver import Driver
 
 
 class EnvDefault(argparse.Action):
···
                 )
         if required and default:
             required = False
-        super(EnvDefault, self).__init__(
-            default=default, required=required, nargs=nargs, **kwargs
-        )
+        super().__init__(default=default, required=required, nargs=nargs, **kwargs)
 
     def __call__(self, parser, namespace, values, option_string=None):  # type: ignore
         setattr(namespace, self.dest, values)

nixos/lib/test-driver/test_driver/driver.py

···
-from contextlib import contextmanager
-from pathlib import Path
-from typing import Any, Dict, Iterator, List, Union, Optional, Callable, ContextManager
 import os
 import re
 import tempfile
+from contextlib import contextmanager
+from pathlib import Path
+from typing import Any, Callable, ContextManager, Dict, Iterator, List, Optional, Union
 
 from test_driver.logger import rootlog
 from test_driver.machine import Machine, NixStartScript, retry
-from test_driver.vlan import VLan
 from test_driver.polling_condition import PollingCondition
+from test_driver.vlan import VLan
 
 
 def get_tmp_dir() -> Path:

nixos/lib/test-driver/test_driver/logger.py

···
 # mypy: disable-error-code="no-untyped-call"
 # drop the above line when mypy is upgraded to include
 # https://github.com/python/typeshed/commit/49b717ca52bf0781a538b04c0d76a5513f7119b8
-from colorama import Style, Fore
-from contextlib import contextmanager
-from typing import Any, Dict, Iterator
-from queue import Queue, Empty
-from xml.sax.saxutils import XMLGenerator
 import codecs
 import os
 import sys
 import time
 import unicodedata
+from contextlib import contextmanager
+from queue import Empty, Queue
+from typing import Any, Dict, Iterator
+from xml.sax.saxutils import XMLGenerator
+
+from colorama import Fore, Style
 
 
 class Logger:

nixos/lib/test-driver/test_driver/machine.py

···
-from contextlib import _GeneratorContextManager, nullcontext
-from pathlib import Path
-from queue import Queue
-from typing import Any, Callable, Dict, Iterable, List, Optional, Tuple
 import base64
 import io
 import os
···
 import tempfile
 import threading
 import time
+from contextlib import _GeneratorContextManager, nullcontext
+from pathlib import Path
+from queue import Queue
+from typing import Any, Callable, Dict, Iterable, List, Optional, Tuple
 
 from test_driver.logger import rootlog
 
···
             return (-1, output.decode())
 
         # Get the return code
-        self.shell.send("echo ${PIPESTATUS[0]}\n".encode())
+        self.shell.send(b"echo ${PIPESTATUS[0]}\n")
         rc = int(self._next_newline_closed_block_from_shell().strip())
 
         return (rc, output.decode(errors="replace"))
···
             return
 
         assert self.shell
-        self.shell.send("poweroff\n".encode())
+        self.shell.send(b"poweroff\n")
         self.wait_for_shutdown()
 
     def crash(self) -> None:

nixos/lib/test-driver/test_driver/polling_condition.py

···
-from typing import Callable, Optional
-from math import isfinite
 import time
+from math import isfinite
+from typing import Callable, Optional
 
 from .logger import rootlog
 

nixos/lib/test-driver/test_driver/vlan.py

···
-from pathlib import Path
 import io
 import os
 import pty
 import subprocess
+from pathlib import Path
 
 from test_driver.logger import rootlog