Add test for new download util

tests/python/unittest/test_download_utils.py

@@ -0,0 +1,49 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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 mxnet as mx
+import mock
+import requests
+import requests_mock
+from nose.tools import *
+
+DATASET_URL = 'http://fakeyannlecun.com/fake.dataset.tar.gz'
+DATASET_FILENAME = 'fake.dataset.tar.gz'
+
+
+@raises(requests.exceptions.HTTPError)
+def test_fake_yann_http_error():
+    # Patch requests so we don't actually issue an http request.
+    with requests_mock.mock() as request_mock:
+        # Patch time so we don't waste time retrying.
+        with mock.patch('time.sleep'):
+            request_mock.get(DATASET_URL, text='Not Found', status_code=404)
+            mx.utils.download(DATASET_URL, overwrite=True)
+
+
+def test_fake_yann_success():
+    # Patch requests so we don't actually issue an http request.
+    with requests_mock.mock() as m:
+        m.get(DATASET_URL, text='data')
+        result = mx.utils.download(DATASET_URL, overwrite=True)
+        assert result == DATASET_FILENAME
+
+
+if __name__ == '__main__':
+
+    import nose
+    nose.runmodule()