added multiple outputs to LightningTestModel

tests/test_models.py

@@ -190,7 +190,9 @@ def test_amp_gpu_ddp():
 
     os.environ['MASTER_PORT'] = str(np.random.randint(12000, 19000, 1)[0])
 
-    model, hparams = get_model()
+    hparams = get_hparams()
+    model = LightningTestModel(hparams)
+
     trainer_options = dict(
         progress_bar=True,
         max_nb_epochs=1,