scripts: migrate format strings to f-strings

scripts/mail-check.py

@@ -14,23 +14,17 @@ RETRY = 100
 def _send_mail(
     smtp_host, smtp_port, smtp_username, from_addr, from_pwd, to_addr, subject, starttls
 ):
-    print("Sending mail with subject '{}'".format(subject))
+    print(f"Sending mail with subject '{subject}'")
     message = "\n".join(
         [
-            "From: {from_addr}",
-            "To: {to_addr}",
-            "Subject: {subject}",
-            "Message-ID: {random}@mail-check.py",
-            "Date: {date}",
+            f"From: {from_addr}",
+            f"To: {to_addr}",
+            f"Subject: {subject}",
+            f"Message-ID: {uuid.uuid4()}@mail-check.py",
+            f"Date: {email.utils.formatdate()}",
             "",
             "This validates our mail server can send to Gmail :/",
         ]
-    ).format(
-        from_addr=from_addr,
-        to_addr=to_addr,
-        subject=subject,
-        random=str(uuid.uuid4()),
-        date=email.utils.formatdate(),
     )
 
     retry = RETRY
@@ -79,7 +73,7 @@ def _read_mail(
     show_body=False,
     delete=True,
 ):
-    print("Reading mail from %s" % imap_username)
+    print("Reading mail from {imap_username}")
 
     message = None
 
@@ -93,7 +87,7 @@ def _read_mail(
     for _ in range(0, RETRY):
         print("Retrying")
         obj.select()
-        _, data = obj.search(None, '(SINCE %s) (SUBJECT "%s")' % (dt, subject))
+        _, data = obj.search(None, f'(SINCE {dt}) (SUBJECT "{subject}")')
         if data == [b""]:
             time.sleep(1)
             continue
@@ -101,8 +95,7 @@ def _read_mail(
         uids = data[0].decode("utf-8").split(" ")
         if len(uids) != 1:
             print(
-                "Warning: %d messages have been found with subject containing %s "
-                % (len(uids), subject)
+                f"Warning: {len(uids)} messages have been found with subject containing {subject}"
             )
 
         # FIXME: we only consider the first matching message...
@@ -113,7 +106,7 @@ def _read_mail(
             obj.expunge()
         assert raw[0] and raw[0][1]
         message = email.message_from_bytes(cast(bytes, raw[0][1]))
-        print("Message with subject '%s' has been found" % message["subject"])
+        print(f"Message with subject '{message['subject']}' has been found")
         if show_body:
             if message.is_multipart():
                 for part in message.walk():
@@ -130,8 +123,7 @@ def _read_mail(
 
     if message is None:
         print(
-            "Error: no message with subject '%s' has been found in INBOX of %s"
-            % (subject, imap_username)
+            f"Error: no message with subject '{subject}' has been found in INBOX of {imap_username}"
         )
         exit(1)
 
@@ -168,7 +160,7 @@ def send_and_read(args):
     else:
         imap_username = args.to_addr
 
-    subject = "{}".format(uuid.uuid4())
+    subject = f"{uuid.uuid4()}"
 
     _send_mail(
         smtp_host=args.smtp_host,