add: check to see if specified pulic/whitelisted urls are actually av…

…ailable in the project

basxbread/apps.py

@@ -1,5 +1,6 @@
 from django.apps import AppConfig
 from django.contrib.messages.constants import DEFAULT_TAGS
+from django.core.checks import Error, register
 from django.utils.translation import gettext as _
 
 
@@ -13,6 +14,24 @@ def ready(self):
         patch_django_filters_verbose_name_func()
 
 
+@register()
+def whitelisted_urls_check(app_configs, **kwargs):
+    from django.conf import settings
+    from django.urls import get_resolver
+
+    errors = []
+    for url in getattr(settings, "PUBLIC_URLS", []):
+        if url not in get_resolver().reverse_dict:
+            errors.append(
+                Error(
+                    "Whitelisted URL not found",
+                    obj=url,
+                    id="basxbread.E001",
+                )
+            )
+    return errors
+
+
 def patch_django_filters_verbose_name_func():
     # django filters verbose_field_name function is not great at using the
     # verbose names on related fields, patching this here