diff --git a/tests/auth_tests/test_models.py b/tests/auth_tests/test_models.py
index 34f411f2f9..983424843c 100644
--- a/tests/auth_tests/test_models.py
+++ b/tests/auth_tests/test_models.py
@@ -433,6 +433,13 @@ class UserWithPermTestCase(TestCase):
                 backend="invalid.backend.CustomModelBackend",
             )
 
+    def test_invalid_backend_submodule(self):
+        with self.assertRaises(ImportError):
+            User.objects.with_perm(
+                "auth.test",
+                backend="json.tool",
+            )
+
     @override_settings(
         AUTHENTICATION_BACKENDS=["auth_tests.test_models.CustomModelBackend"]
     )
diff --git a/tests/auth_tests/test_validators.py b/tests/auth_tests/test_validators.py
index 4da031a793..506c85c0ae 100644
--- a/tests/auth_tests/test_validators.py
+++ b/tests/auth_tests/test_validators.py
@@ -14,7 +14,7 @@ from django.contrib.auth.password_validation import (
     password_validators_help_texts,
     validate_password,
 )
-from django.core.exceptions import ValidationError
+from django.core.exceptions import ImproperlyConfigured, ValidationError
 from django.db import models
 from django.test import SimpleTestCase, TestCase, override_settings
 from django.test.utils import isolate_apps
@@ -50,6 +50,15 @@ class PasswordValidationTest(SimpleTestCase):
 
         self.assertEqual(get_password_validators([]), [])
 
+    def test_get_password_validators_custom_invalid(self):
+        validator_config = [{"NAME": "json.tool"}]
+        msg = (
+            "The module in NAME could not be imported: json.tool. "
+            "Check your AUTH_PASSWORD_VALIDATORS setting."
+        )
+        with self.assertRaisesMessage(ImproperlyConfigured, msg):
+            get_password_validators(validator_config)
+
     def test_validate_password(self):
         self.assertIsNone(validate_password("sufficiently-long"))
         msg_too_short = (