[2.0.x] Fixed #28941 -- Fixed crash in testserver command startup.

Regression in 2b09e4c88e.

Backport of e7b804c060 from master

django/core/management/commands/runserver.py

@@ -27,6 +27,7 @@ class Command(BaseCommand):
     # Validation is called explicitly each time the server is reloaded.
     requires_system_checks = False
     leave_locale_alone = True
+    stealth_options = ('shutdown_message',)
 
     default_addr = '127.0.0.1'
     default_addr_ipv6 = '::1'

docs/releases/2.0.1.txt

@@ -29,3 +29,5 @@ Bugfixes
 
 * Fixed a regression on SQLite where ``DecimalField`` returned a result with
   trailing zeros in the fractional part truncated (:ticket:`28915`).
+
+* Fixed crash in the ``testserver`` command startup (:ticket:`28941`).

tests/admin_scripts/tests.py

@@ -21,7 +21,9 @@ from django.conf import settings
 from django.core.management import (
     BaseCommand, CommandError, call_command, color,
 )
-from django.db import ConnectionHandler
+from django.core.management.commands.loaddata import Command as LoaddataCommand
+from django.core.management.commands.runserver import Command as RunserverCommand
+from django.db import ConnectionHandler, connection
 from django.db.migrations.recorder import MigrationRecorder
 from django.test import (
     LiveServerTestCase, SimpleTestCase, TestCase, override_settings,
@@ -1406,6 +1408,31 @@ class ManageTestserver(AdminScriptTestCase):
             skip_checks=True, interactive=True,
         )
 
+    @mock.patch('django.db.connection.creation.create_test_db', return_value='test_db')
+    @mock.patch.object(LoaddataCommand, 'handle', return_value='')
+    @mock.patch.object(RunserverCommand, 'handle', return_value='')
+    def test_params_to_runserver(self, mock_runserver_handle, mock_loaddata_handle, mock_create_test_db):
+        out = StringIO()
+        call_command('testserver', 'blah.json', stdout=out)
+        mock_runserver_handle.assert_called_with(
+            addrport='',
+            insecure_serving=False,
+            no_color=False,
+            pythonpath=None,
+            settings=None,
+            shutdown_message=(
+                "\nServer stopped.\nNote that the test database, 'test_db', "
+                "has not been deleted. You can explore it on your own."
+            ),
+            skip_checks=True,
+            traceback=False,
+            use_ipv6=False,
+            use_reloader=False,
+            use_static_handler=True,
+            use_threading=connection.features.test_db_allows_multiple_connections,
+            verbosity=1,
+        )
+
 
 ##########################################################################
 # COMMAND PROCESSING TESTS