Add (failing) tests for Keras save/load

tests/test_modeling_tf_common.py

@@ -19,8 +19,10 @@ import os
 import random
 import tempfile
 import unittest
+from importlib import import_module
 
 from transformers import is_tf_available, is_torch_available
+from transformers.modeling_tf_utils import TFMainLayer
 
 from .utils import _tf_gpu_memory_limit, require_tf
 
@@ -88,7 +90,38 @@ class TFModelTesterMixin:
                 model.save_pretrained(tmpdirname)
                 model = model_class.from_pretrained(tmpdirname)
                 after_outputs = model(inputs_dict)
+                self.assert_outputs_same(after_outputs, outputs)
 
+    def test_keras_save_load(self):
+        config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()
+
+        tf_main_layer_classes = set(
+            module_member
+            for model_class in self.all_model_classes
+            for module in (import_module(model_class.__module__),)
+            for module_member_name in dir(module)
+            for module_member in (getattr(module, module_member_name),)
+            if isinstance(module_member, type) and TFMainLayer in module_member.__bases__
+        )
+        for main_layer_class in tf_main_layer_classes:
+            main_layer = main_layer_class(config)
+            symbolic_inputs = {
+                name: tf.keras.Input(tensor.shape[1:], dtype=tensor.dtype) for name, tensor in inputs_dict.items()
+            }
+            model = tf.keras.Model(symbolic_inputs, outputs=main_layer(symbolic_inputs))
+            outputs = model(inputs_dict)
+
+            with tempfile.TemporaryDirectory() as tmpdirname:
+                filepath = os.path.join(tmpdirname, "keras_model.h5")
+                model.save(filepath)
+                model = tf.keras.models.load_model(
+                    filepath, custom_objects={main_layer_class.__name__: main_layer_class}
+                )
+                assert isinstance(model, tf.keras.Model)
+                after_outputs = model(inputs_dict)
+                self.assert_outputs_same(after_outputs, outputs)
+
+    def assert_outputs_same(self, after_outputs, outputs):
         # Make sure we don't have nans
         out_1 = after_outputs[0].numpy()
         out_2 = outputs[0].numpy()