move assertion instead of removing it

otherwise the tool test will just return a list out of bounds exception
which is unclear to the user

lib/galaxy/tool_util/verify/interactor.py

@@ -1486,7 +1486,6 @@ def _handle_def_errors(testdef):
 def _verify_outputs(testdef, history, jobs, data_list, data_collection_list, galaxy_interactor, quiet=False):
     assert len(jobs) == 1, "Test framework logic error, somehow tool test resulted in more than one job."
     job = jobs[0]
-
     found_exceptions: List[Exception] = []
 
     def register_exception(e: Exception):
@@ -1501,6 +1500,9 @@ def register_exception(e: Exception):
         if testdef.outputs:
             raise Exception("Cannot specify outputs in a test expecting failure.")
 
+    if not data_list and not data_collection_list:
+        Exception("Job did not produce any outputs")
+
     maxseconds = testdef.maxseconds
     # Wait for the job to complete and register expections if the final
     # status was not what test was expecting.