Allow passing encoder_ouputs as tuple to EncoderDecoder Models (#16814)

* Add passing encoder_outputs as tuple to existing test

* Add check for tuple

* Add check for tuple also for speech and vision

Co-authored-by: jsnfly <jsnfly@gmx.de>

tests/encoder_decoder/test_modeling_encoder_decoder.py

@@ -142,6 +142,22 @@ class EncoderDecoderMixin:
             outputs_encoder_decoder["encoder_last_hidden_state"].shape, (input_ids.shape + (config.hidden_size,))
         )
 
+        # Test passing encoder_outputs as tuple.
+        encoder_outputs = (encoder_hidden_states,)
+        outputs_encoder_decoder = enc_dec_model(
+            encoder_outputs=encoder_outputs,
+            decoder_input_ids=decoder_input_ids,
+            attention_mask=attention_mask,
+            decoder_attention_mask=decoder_attention_mask,
+        )
+
+        self.assertEqual(
+            outputs_encoder_decoder["logits"].shape, (decoder_input_ids.shape + (decoder_config.vocab_size,))
+        )
+        self.assertEqual(
+            outputs_encoder_decoder["encoder_last_hidden_state"].shape, (input_ids.shape + (config.hidden_size,))
+        )
+
     def check_encoder_decoder_model_from_pretrained_using_model_paths(
         self,
         config,