Fixed #26327 -- Added JsonAgg to contrib.postgres.

Thanks Tim Graham for review.

1 files changed, 22 insertions, 5 deletions

diff --git a/tests/postgres_tests/test_aggregates.py b/tests/postgres_tests/test_aggregates.py
index f6f48fdd61..aaab3b1bc6 100644
--- a/tests/postgres_tests/test_aggregates.py
+++ b/tests/postgres_tests/test_aggregates.py
@@ -1,14 +1,21 @@
-from django.contrib.postgres.aggregates import (
-    ArrayAgg, BitAnd, BitOr, BoolAnd, BoolOr, Corr, CovarPop, RegrAvgX,
-    RegrAvgY, RegrCount, RegrIntercept, RegrR2, RegrSlope, RegrSXX, RegrSXY,
-    RegrSYY, StatAggregate, StringAgg,
-)
+import json
+
 from django.db.models.expressions import F, Value
+from django.test.testcases import skipUnlessDBFeature
 from django.test.utils import Approximate
 
 from . import PostgreSQLTestCase
 from .models import AggregateTestModel, StatTestModel
 
+try:
+    from django.contrib.postgres.aggregates import (
+        ArrayAgg, BitAnd, BitOr, BoolAnd, BoolOr, Corr, CovarPop, JsonAgg,
+        RegrAvgX, RegrAvgY, RegrCount, RegrIntercept, RegrR2, RegrSlope,
+        RegrSXX, RegrSXY, RegrSYY, StatAggregate, StringAgg,
+    )
+except ImportError:
+    pass  # psycopg2 is not installed
+
 
 class TestGeneralAggregate(PostgreSQLTestCase):
     @classmethod
@@ -110,6 +117,16 @@ class TestGeneralAggregate(PostgreSQLTestCase):
         values = AggregateTestModel.objects.aggregate(stringagg=StringAgg('char_field', delimiter=';'))
         self.assertEqual(values, {'stringagg': ''})
 
+    @skipUnlessDBFeature('has_jsonb_datatype')
+    def test_json_agg(self):
+        values = AggregateTestModel.objects.aggregate(jsonagg=JsonAgg('char_field'))
+        self.assertEqual(values, {'jsonagg': ['Foo1', 'Foo2', 'Foo3', 'Foo4']})
+
+    @skipUnlessDBFeature('has_jsonb_datatype')
+    def test_json_agg_empty(self):
+        values = AggregateTestModel.objects.none().aggregate(jsonagg=JsonAgg('integer_field'))
+        self.assertEqual(values, json.loads('{"jsonagg": []}'))
+
 
 class TestStringAggregateDistinct(PostgreSQLTestCase):
     @classmethod