diff --git a/tests/postgres_tests/test_array.py b/tests/postgres_tests/test_array.py
index ee66fbcd60c..df95e251ec4 100644
--- a/tests/postgres_tests/test_array.py
+++ b/tests/postgres_tests/test_array.py
@@ -489,7 +489,9 @@ class TestQuerying(PostgreSQLTestCase):
         value = models.Value([1], output_field=ArrayField(models.IntegerField()))
         self.assertEqual(
             NullableIntegerArrayModel.objects.annotate(
-                array_length=models.Func(value, 1, function='ARRAY_LENGTH'),
+                array_length=models.Func(
+                    value, 1, function='ARRAY_LENGTH', output_field=models.IntegerField(),
+                ),
             ).values('array_length').annotate(
                 count=models.Count('pk'),
             ).get()['array_length'],