add unittest for datasets

tests/test_datasets.py

+# Copyright (c) 2020 PaddlePaddle Authors. 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.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+
+import unittest
+import sys
+sys.path.append('..')
+
+from datasets.folder import DatasetFolder
+
+
+class TestFolderDatasets(unittest.TestCase):
+    def test_dataset(self):
+        dataset_folder = DatasetFolder('test_data')
+
+        for _ in dataset_folder:
+            pass
+
+        assert len(dataset_folder) == 3
+        assert len(dataset_folder.classes) == 2
+
+
+if __name__ == '__main__':
+    unittest.main()