fix: honor source_dir from S3

Author: mvsusp

tests/data/tfs/tfs-test-entrypoint-with-handler/123/assets/foo.txt

@@ -0,0 +1 @@
+asset-file-contents

tests/data/tfs/tfs-test-entrypoint-with-handler/123/saved_model.pb

@@ -0,0 +1,43 @@
+# Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+
+"""Exports a toy TensorFlow model.
+Exports a TensorFlow model to /opt/ml/model/
+This graph calculates,
+  y = a*x + b
+where a and b are variables with a=0.5 and b=2.
+"""
+import json
+import shutil
+
+
+def save_model():
+    shutil.copytree('/opt/ml/code/123', '/opt/ml/model/123')
+
+
+def input_handler(data, context):
+    data = json.loads(data.read().decode('utf-8'))
+    new_values = [x + 1 for x in data['instances']]
+    dumps = json.dumps({'instances': new_values})
+    return dumps
+
+
+def output_handler(data, context):
+    response_content_type = context.accept_header
+    prediction = data.content
+    return prediction, response_content_type
+
+
+if __name__ == "__main__":
+    save_model()
+