Fix friend_code max length issues in tests, and fix in_game_name length issues, also update tests to fit more scenarios

trades/mixins.py

@@ -1,4 +1,5 @@
 from cards.models import Card
+from django.core.exceptions import PermissionDenied
 
 class TradeOfferContextMixin:
     def get_context_data(self, **kwargs):
@@ -20,4 +21,17 @@ class TradeOfferContextMixin:
             selected_friend_code = self.request.user.default_friend_code or friend_codes.first()
         context["selected_friend_code"] = selected_friend_code
         
-        return context 
+        return context 
+
+class FriendCodeRequiredMixin:
+    """
+    Mixin to ensure the authenticated user has at least one friend code.
+    This mixin must be placed after LoginRequiredMixin in the view's inheritance order.
+    """
+    def dispatch(self, request, *args, **kwargs):
+        # Since LoginRequiredMixin guarantees that request.user is authenticated,
+        # we assume request.user has the attribute `friend_codes`. If no friend code exists,
+        # raise a PermissionDenied error.
+        if not getattr(request.user, 'friend_codes', None) or not request.user.friend_codes.exists():
+            raise PermissionDenied("No friend codes available for your account.")
+        return super().dispatch(request, *args, **kwargs)