[examples] fix summarization do_predict (#3866)

examples/summarization/bart/finetune.py

@@ -166,8 +166,12 @@ def main(args):
 
     # Optionally, predict on dev set and write to output_dir
     if args.do_predict:
+        # See https://github.com/huggingface/transformers/issues/3159
+        # pl use this format to create a checkpoint:
+        # https://github.com/PyTorchLightning/pytorch-lightning/blob/master\
+        # /pytorch_lightning/callbacks/model_checkpoint.py#L169
         checkpoints = list(sorted(glob.glob(os.path.join(args.output_dir, "checkpointepoch=*.ckpt"), recursive=True)))
-        SummarizationTrainer.load_from_checkpoint(checkpoints[-1])
+        model = model.load_from_checkpoint(checkpoints[-1])
         trainer.test(model)
 
 

examples/summarization/bart/test_bart_examples.py

@@ -94,7 +94,15 @@ class TestBartExamples(unittest.TestCase):
         )
         main(argparse.Namespace(**args_d))
         args_d.update({"do_train": False, "do_predict": True})
+
         main(argparse.Namespace(**args_d))
+        contents = os.listdir(output_dir)
+        expected_contents = {
+            "checkpointepoch=0.ckpt",
+            "test_results.txt",
+        }
+        created_files = {os.path.basename(p) for p in contents}
+        self.assertSetEqual(expected_contents, created_files)
 
     def test_t5_run_sum_cli(self):
         args_d: dict = DEFAULT_ARGS.copy()
@@ -111,6 +119,7 @@ class TestBartExamples(unittest.TestCase):
             do_predict=True,
         )
         main(argparse.Namespace(**args_d))
+
         # args_d.update({"do_train": False, "do_predict": True})
         # main(argparse.Namespace(**args_d))