Send email to user when a checker fails, eg: with weak password login at...

secure_login/backends.py

@@ -25,9 +25,16 @@ def authenticate(self, username=None, password=None, **kwargs):
                                     "SECURE_LOGIN_ON_FAIL",
                                     DEFAULT_ON_FAIL)
 
+        checker_failed = False
         for checker in checkers:
             if not get_callable(checker)(username, password, **kwargs):
-                return None
+                checker_failed = True
+                break
+        if checker_failed:
+            for callable_ in on_fail_callables:
+                get_callable(callable_)(username, password, **kwargs)
+            return None
+
         user = super(SecureLoginBackendMixin, self).authenticate(username,
                                                                  password,
                                                                  **kwargs)

secure_login/tests.py

@@ -78,3 +78,20 @@ def test_email_sent_on_wrong_password(self):
         self.assertFalse(authenticate(username=username,
                                       password=password + "1"))
         self.assertEqual(len(mail.outbox), 1)
+
+    @override_settings(
+        SECURE_LOGIN_CHECKERS=[
+            "secure_login.checkers.no_weak_passwords",
+        ]
+    )
+    def test_email_sent_on_weak_password(self):
+        username = "hello"
+        password = "hello"
+        good_password = "a-l0ng-pa55w0rd-@^&"
+        user = User.objects.create(username=username)
+        user.set_password(good_password)
+        user.save()
+
+        self.assertFalse(authenticate(username=username,
+                                      password=password))
+        self.assertEqual(len(mail.outbox), 1)