Update tests so they also pass with datastore emulator and add

Kami · Kami · commit abc53733cabe · 2019-07-18T15:47:35.000+02:00
additional asserts.

Datastore doesn't support such large number of items so we use a smaller
number.
diff --git a/datastore/tests/system/test_system.py b/datastore/tests/system/test_system.py
@@ -398,13 +398,21 @@ def test_query_paginate_simple_timestamp_keys(self):
 
     def test_query_offset_timestamp_keys(self):
         # See issue #4675
-        max_all = 10000
+        max_all = 1000
         offset = 1
         max_offset = max_all - offset
         query = self.CLIENT.query(kind="timestamp_key")
         all_w_limit = list(query.fetch(limit=max_all))
+
         self.assertEqual(len(all_w_limit), max_all)
 
+        offset = 1
+        max_offset = max_all - offset
+        offset_w_limit = list(query.fetch(offset=offset, limit=max_offset))
+        self.assertEqual(offset_w_limit, all_w_limit[offset:])
+
+        offset = 50
+        max_offset = max_all - offset
         offset_w_limit = list(query.fetch(offset=offset, limit=max_offset))
         self.assertEqual(offset_w_limit, all_w_limit[offset:])
 
