Improved ExplainTests.test_basic().

QuerySet.select_for_update() is not supported by all databases.
Moreover it cannot be used outside of a transaction.

1 files changed, 14 insertions, 7 deletions

diff --git a/tests/queries/test_explain.py b/tests/queries/test_explain.py
index f8ec9f445d..1d17ef8191 100644
--- a/tests/queries/test_explain.py
+++ b/tests/queries/test_explain.py
@@ -20,8 +20,9 @@ class ExplainTests(TestCase):
             Tag.objects.filter(name="test").annotate(Count("children")),
             Tag.objects.filter(name="test").values_list("name"),
             Tag.objects.order_by().union(Tag.objects.order_by().filter(name="test")),
-            Tag.objects.select_for_update().filter(name="test"),
         ]
+        if connection.features.has_select_for_update:
+            querysets.append(Tag.objects.select_for_update().filter(name="test"))
         supported_formats = connection.features.supported_explain_formats
         all_formats = (
             (None,)
@@ -31,13 +32,19 @@ class ExplainTests(TestCase):
         for idx, queryset in enumerate(querysets):
             for format in all_formats:
                 with self.subTest(format=format, queryset=idx):
-                    with self.assertNumQueries(1), CaptureQueriesContext(
-                        connection
-                    ) as captured_queries:
-                        result = queryset.explain(format=format)
+                    with CaptureQueriesContext(connection) as captured_queries:
+                        if queryset.query.select_for_update:
+                            with transaction.atomic():
+                                result = queryset.explain(format=format)
+                        else:
+                            result = queryset.explain(format=format)
+                            self.assertEqual(len(captured_queries), 1)
                         self.assertTrue(
-                            captured_queries[0]["sql"].startswith(
-                                connection.ops.explain_prefix
+                            any(
+                                captured_query["sql"].startswith(
+                                    connection.ops.explain_prefix
+                                )
+                                for captured_query in captured_queries
                             )
                         )
                         self.assertIsInstance(result, str)