diff --git a/bopytex/planner/generate_compile_join_planner.py b/bopytex/planner/generate_compile_join_planner.py
index 28e30cb..8fd2ad2 100644
--- a/bopytex/planner/generate_compile_join_planner.py
+++ b/bopytex/planner/generate_compile_join_planner.py
@@ -23,11 +23,13 @@ def build_subject_list_from_qty(qty: int) -> list[dict]:
 def planner(options: dict) -> list[Task]:
     try:
         students_csv = options["students_csv"]
+        assert options["students_csv"] != ""
 
-    except KeyError:
+    except (KeyError, AssertionError):
         try:
             quantity_subjects = options["quantity_subjects"]
-        except KeyError:
+            assert options["quantity_subjects"] != 0
+        except (KeyError, AssertionError):
             raise PlannerMissingOption("students_csv or quantity_subjects is required")
         else:
             options["subjects"] = build_subject_list_from_qty(qty=quantity_subjects)