added saving tests to cpu

pytorch_lightning/root_module/model_saving.py

@@ -86,7 +86,7 @@ class TrainerIO(object):
     # --------------------
     # HPC IO
     # --------------------
-    def enable_auto_hpc_walltime_manager(self):  # pragma: no cover
+    def enable_auto_hpc_walltime_manager(self):
         if self.cluster is None:
             return
 
@@ -157,6 +157,8 @@ class TrainerIO(object):
         # do the actual save
         torch.save(checkpoint_dict, filepath)
 
+        return filepath
+
     def hpc_load(self, folderpath, on_gpu):
         filepath = '{}/hpc_ckpt_{}.ckpt'.format(folderpath, self.max_ckpt_in_folder(folderpath))