Create separate methods for getting messages to push

for the email and http pushers rather than trying to make a single
method that will work with their conflicting requirements.

The http pusher needs to get the messages in ascending stream order, and
doesn't want to miss a message.

The email pusher needs to get the messages in descending timestamp order,
and doesn't mind if it misses messages.

tests/storage/test_event_push_actions.py

@@ -0,0 +1,41 @@
+# -*- coding: utf-8 -*-
+# Copyright 2016 OpenMarket Ltd
+#
+# 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.
+
+from twisted.internet import defer
+
+import tests.unittest
+import tests.utils
+
+USER_ID = "@user:example.com"
+
+
+class EventPushActionsStoreTestCase(tests.unittest.TestCase):
+
+    @defer.inlineCallbacks
+    def setUp(self):
+        hs = yield tests.utils.setup_test_homeserver()
+        self.store = hs.get_datastore()
+
+    @defer.inlineCallbacks
+    def test_get_unread_push_actions_for_user_in_range_for_http(self):
+        yield self.store.get_unread_push_actions_for_user_in_range_for_http(
+            USER_ID, 0, 1000, 20
+        )
+
+    @defer.inlineCallbacks
+    def test_get_unread_push_actions_for_user_in_range_for_email(self):
+        yield self.store.get_unread_push_actions_for_user_in_range_for_email(
+            USER_ID, 0, 1000, 20
+        )