Refs #30158 -- Added alias argument to Expression.get_group_by_cols().

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/expressions/test_deprecation.py b/tests/expressions/test_deprecation.py
new file mode 100644
index 0000000000..cdb1e43af6
--- /dev/null
+++ b/tests/expressions/test_deprecation.py
@@ -0,0 +1,24 @@
+from django.db.models import Count, Func
+from django.test import SimpleTestCase
+from django.utils.deprecation import RemovedInDjango40Warning
+
+from .models import Employee
+
+
+class MissingAliasFunc(Func):
+    template = '1'
+
+    def get_group_by_cols(self):
+        return []
+
+
+class GetGroupByColsTest(SimpleTestCase):
+    def test_missing_alias(self):
+        msg = (
+            '`alias=None` must be added to the signature of '
+            'expressions.test_deprecation.MissingAliasFunc.get_group_by_cols().'
+        )
+        with self.assertRaisesMessage(RemovedInDjango40Warning, msg):
+            Employee.objects.values(
+                one=MissingAliasFunc(),
+            ).annotate(cnt=Count('company_ceo_set'))