create_user: Extract get_create_user_params.

We set nocoverage for the new function. Ideally it'd eventually get an
automated test, but we don't want to block this helpful refactoring on
doing so.

zerver/lib/management.py

@@ -1,11 +1,15 @@
 # Library code for use in management commands
+import logging
 from argparse import SUPPRESS, ArgumentParser, RawTextHelpFormatter
+from dataclasses import dataclass
 from typing import Any, Dict, List, Optional
 
 from django.conf import settings
-from django.core.exceptions import MultipleObjectsReturned
+from django.core import validators
+from django.core.exceptions import MultipleObjectsReturned, ValidationError
 from django.core.management.base import BaseCommand, CommandError, CommandParser
 
+from zerver.lib.initial_password import initial_password
 from zerver.models import Client, Realm, UserProfile, get_client
 
 
@@ -30,6 +34,13 @@ def check_config() -> None:
         raise CommandError(f"Error: You must set {setting_name} in /etc/zulip/settings.py.")
 
 
+@dataclass
+class CreateUserParameters:
+    email: str
+    full_name: str
+    password: Optional[str]
+
+
 class ZulipBaseCommand(BaseCommand):
 
     # Fix support for multi-line usage
@@ -167,3 +178,49 @@ server via `ps -ef` or reading bash history. Prefer
     def get_client(self) -> Client:
         """Returns a Zulip Client object to be used for things done in management commands"""
         return get_client("ZulipServer")
+
+    def get_create_user_params(self, options: Dict[str, Any]) -> CreateUserParameters:  # nocoverage
+        """
+        Parses parameters for user creation defined in add_create_user_args.
+        """
+        if "email" not in options:
+            email = input("Email: ")
+        else:
+            email = options["email"]
+
+        try:
+            validators.validate_email(email)
+        except ValidationError:
+            raise CommandError("Invalid email address.")
+
+        if "full_name" not in options:
+            full_name = input("Full name: ")
+        else:
+            full_name = options["full_name"]
+
+        if options["password_file"] is not None:
+            with open(options["password_file"]) as f:
+                password: Optional[str] = f.read().strip()
+        elif options["password"] is not None:
+            logging.warning(
+                "Passing password on the command line is insecure; prefer --password-file."
+            )
+            password = options["password"]
+        else:
+            # initial_password will return a random password that
+            # is a salted hash of the email address in a
+            # development environment, and None in a production
+            # environment.
+            user_initial_password = initial_password(email)
+            if user_initial_password is None:
+                logging.info("User will be created with a disabled password.")
+            else:
+                assert settings.DEVELOPMENT
+                logging.info("Password will be available via `./manage.py print_initial_password`.")
+            password = user_initial_password
+
+        return CreateUserParameters(
+            email=email,
+            full_name=full_name,
+            password=password,
+        )

zerver/management/commands/create_user.py

@@ -1,15 +1,10 @@
 import argparse
-import logging
-from typing import Any, Optional
+from typing import Any
 
-from django.conf import settings
-from django.core import validators
-from django.core.exceptions import ValidationError
 from django.core.management.base import CommandError
 from django.db.utils import IntegrityError
 
 from zerver.lib.actions import do_create_user
-from zerver.lib.initial_password import initial_password
 from zerver.lib.management import ZulipBaseCommand
 
 
@@ -31,48 +26,14 @@ Omit both <email> and <full name> for interactive user creation.
         realm = self.get_realm(options)
         assert realm is not None  # Should be ensured by parser
 
-        if "email" not in options:
-            email = input("Email: ")
-        else:
-            email = options["email"]
-
-        try:
-            validators.validate_email(email)
-        except ValidationError:
-            raise CommandError("Invalid email address.")
-
-        if "full_name" not in options:
-            full_name = input("Full name: ")
-        else:
-            full_name = options["full_name"]
-
-        if options["password_file"] is not None:
-            with open(options["password_file"]) as f:
-                password: Optional[str] = f.read().strip()
-        elif options["password"] is not None:
-            logging.warning(
-                "Passing password on the command line is insecure; prefer --password-file."
-            )
-            password = options["password"]
-        else:
-            # initial_password will return a random password that
-            # is a salted hash of the email address in a
-            # development environment, and None in a production
-            # environment.
-            user_initial_password = initial_password(email)
-            if user_initial_password is None:
-                logging.info("User will be created with a disabled password.")
-            else:
-                assert settings.DEVELOPMENT
-                logging.info("Password will be available via `./manage.py print_initial_password`.")
-            password = user_initial_password
+        create_user_params = self.get_create_user_params(options)
 
         try:
             do_create_user(
-                email,
-                password,
+                create_user_params.email,
+                create_user_params.password,
                 realm,
-                full_name,
+                create_user_params.full_name,
                 # Explicitly set tos_version=None. For servers that
                 # have configured Terms of Service, this means that
                 # users created via this mechanism will be prompted to