Add backend tests from glance

Moves some unit tests that were part of glance but should have
belonged to glance_store.

These tests are ported from
glance/tests/unit/test_store_image.py

Change-Id: I688629d37e9146aef33fbc9bb6fd8780521e06ab

glance_store/tests/unit/test_backend.py

@@ -0,0 +1,115 @@
+# Copyright 2016 OpenStack, LLC
+# 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.
+
+"""Tests the backend store API's"""
+
+import mock
+
+from glance_store import backend
+from glance_store import exceptions
+from glance_store.tests import base
+
+
+class TestStoreAddToBackend(base.StoreBaseTest):
+
+    def setUp(self):
+        super(TestStoreAddToBackend, self).setUp()
+        self.image_id = "animage"
+        self.data = "dataandstuff"
+        self.size = len(self.data)
+        self.location = "file:///ab/cde/fgh"
+        self.checksum = "md5"
+
+    def _bad_metadata(self, in_metadata):
+        mstore = mock.Mock()
+        mstore.add.return_value = (self.location, self.size,
+                                   self.checksum, in_metadata)
+        mstore.__str__ = lambda self: "hello"
+        mstore.__unicode__ = lambda self: "hello"
+
+        self.assertRaises(exceptions.BackendException,
+                          backend.store_add_to_backend,
+                          self.image_id,
+                          self.data,
+                          self.size,
+                          mstore)
+
+        mstore.add.assert_called_once_with(self.image_id, mock.ANY,
+                                           self.size, context=None,
+                                           verifier=None)
+
+    def _good_metadata(self, in_metadata):
+        mstore = mock.Mock()
+        mstore.add.return_value = (self.location, self.size,
+                                   self.checksum, in_metadata)
+
+        (location,
+         size,
+         checksum,
+         metadata) = backend.store_add_to_backend(self.image_id,
+                                                  self.data,
+                                                  self.size,
+                                                  mstore)
+
+        mstore.add.assert_called_once_with(self.image_id, mock.ANY,
+                                           self.size, context=None,
+                                           verifier=None)
+
+        self.assertEqual(self.location, location)
+        self.assertEqual(self.size, size)
+        self.assertEqual(self.checksum, checksum)
+        self.assertEqual(in_metadata, metadata)
+
+    def test_empty(self):
+        metadata = {}
+        self._good_metadata(metadata)
+
+    def test_string(self):
+        metadata = {'key': u'somevalue'}
+        self._good_metadata(metadata)
+
+    def test_list(self):
+        m = {'key': [u'somevalue', u'2']}
+        self._good_metadata(m)
+
+    def test_unicode_dict(self):
+        inner = {'key1': u'somevalue', 'key2': u'somevalue'}
+        m = {'topkey': inner}
+        self._good_metadata(m)
+
+    def test_unicode_dict_list(self):
+        inner = {'key1': u'somevalue', 'key2': u'somevalue'}
+        m = {'topkey': inner, 'list': [u'somevalue', u'2'], 'u': u'2'}
+        self._good_metadata(m)
+
+    def test_nested_dict(self):
+        inner = {'key1': u'somevalue', 'key2': u'somevalue'}
+        inner = {'newkey': inner}
+        inner = {'anotherkey': inner}
+        m = {'topkey': inner}
+        self._good_metadata(m)
+
+    def test_bad_top_level_nonunicode(self):
+        metadata = {'key': b'a string'}
+        self._bad_metadata(metadata)
+
+    def test_bad_nonunicode_dict_list(self):
+        inner = {'key1': u'somevalue', 'key2': u'somevalue',
+                 'k3': [1, object()]}
+        m = {'topkey': inner, 'list': [u'somevalue', u'2'], 'u': u'2'}
+        self._bad_metadata(m)
+
+    def test_bad_metadata_not_dict(self):
+        self._bad_metadata([])