Fixed expected num queries for MySQL

simple_history/tests/tests/test_manager.py

@@ -3,7 +3,7 @@
 
 import django
 from django.contrib.auth import get_user_model
-from django.db import IntegrityError
+from django.db import IntegrityError, connection
 from django.test import TestCase, override_settings, skipUnlessDBFeature
 
 from simple_history.manager import SIMPLE_HISTORY_REVERSE_ATTR_NAME
@@ -151,6 +151,9 @@ def test_historical_query_set(self):
         """
         Demonstrates how the HistoricalQuerySet works to provide as_of functionality.
         """
+        backend = connection.vendor
+        expected_latest_of_each_queries = 2 if backend == "mysql" else 1
+
         document1 = RankedDocument.objects.create(rank=42)
         document2 = RankedDocument.objects.create(rank=84)
         document2.rank = 51
@@ -164,15 +167,15 @@ def test_historical_query_set(self):
             self.assertEqual(queryset.count(), 4)
 
         # only want the most recent records (provided by HistoricalQuerySet)
-        with self.assertNumQueries(1):
+        with self.assertNumQueries(expected_latest_of_each_queries):
             self.assertEqual(queryset.latest_of_each().count(), 2)
 
         # want to see the instances as of that time?
-        with self.assertNumQueries(1):
+        with self.assertNumQueries(expected_latest_of_each_queries):
             self.assertEqual(queryset.latest_of_each().as_instances().count(), 1)
 
         # these new methods are idempotent
-        with self.assertNumQueries(1):
+        with self.assertNumQueries(expected_latest_of_each_queries):
             self.assertEqual(
                 queryset.latest_of_each()
                 .latest_of_each()