smtpdummy: Fix warnings

hm/scripts/smtpdummy

@@ -19,8 +19,8 @@ if __name__ == "__main__":
         description="Generate SMTP messages to send a mail"
     )
 
-    now = datetime.datetime.now()
-    now_email = email.utils.formatdate(now.timestamp(), True)
+    now = datetime.datetime.now(tz=datetime.UTC).astimezone()
+    now_email = email.utils.formatdate(now.timestamp(), localtime=True)
 
     parser.add_argument("-o", "--origin", env_var="ORIGIN", default="localhost")
     parser.add_argument(
@@ -89,7 +89,7 @@ if __name__ == "__main__":
         args.reply_to = getattr(args, "from")
     if args.password:
         password = args.password
-        args.password = "********"
+        args.password = "********"  # noqa: S105
     mid = email.utils.make_msgid(domain=args.helo)
 
     # Transmission content
@@ -109,7 +109,7 @@ XJS*C4JDBQADN1.NSBN3*2IDNEN*GTUBE-STANDARD-ANTI-UBE-TEST-EMAIL*C.34X"""
         body = f"\n\n{args.body}"
 
     text = f"""Date: {now_email}
-From: {args.me} <{getattr(args, 'from')}>
+From: {args.me} <{getattr(args, "from")}>
 Subject: {args.subject}
 To: {args.to}
 Reply-To: {args.reply_to}
@@ -127,7 +127,7 @@ Input arguments:
 
 -- 
 {args.me}
-."""
+."""  # noqa: W291
 
     # Transmission setup
     cmd = []
@@ -160,24 +160,27 @@ Input arguments:
             stderr=subprocess.DEVNULL,
         )
 
+    SMTP_ERROR_CODES_START = 400
+
     def recv() -> None:
         if args.dryrun:
             return
 
         assert isinstance(p.stdout, io.BufferedReader)
-        next = True
-        while next:
+        more = True
+        while more:
             line = p.stdout.readline()
             try:
                 code = int(line[:3])
-            except ValueError:
-                raise ValueError(f"Could not parse line: '{line.decode()}'")
-            success = code < 400
+            except ValueError as err:
+                msg = f"Could not parse line: '{line.decode()}'"
+                raise ValueError(msg) from err
+            success = code < SMTP_ERROR_CODES_START
             color = colorama.Fore.GREEN if success else colorama.Fore.RED
             if not args.quiet:
                 print(color + f"< {line[:-1].decode()}" + colorama.Fore.RESET)
-            next = line[3] == b"-"[0]
-            if not next and not success:
+            more = line[3] == b"-"[0]
+            if not more and not success:
                 send("QUIT")  # TODO Can loop if QUIT fails
                 sys.exit(1)