Fixed #24060 -- Added OrderBy Expressions

1 files changed, 62 insertions, 0 deletions

diff --git a/tests/ordering/tests.py b/tests/ordering/tests.py
index 5d323e006b..abb30f43f1 100644
--- a/tests/ordering/tests.py
+++ b/tests/ordering/tests.py
@@ -3,6 +3,7 @@ from __future__ import unicode_literals
 from datetime import datetime
 from operator import attrgetter
 
+from django.db.models import F
 from django.test import TestCase
 
 from .models import Article, Author
@@ -203,3 +204,64 @@ class OrderingTests(TestCase):
             ],
             attrgetter("headline")
         )
+
+    def test_order_by_f_expression(self):
+        self.assertQuerysetEqual(
+            Article.objects.order_by(F('headline')), [
+                "Article 1",
+                "Article 2",
+                "Article 3",
+                "Article 4",
+            ],
+            attrgetter("headline")
+        )
+        self.assertQuerysetEqual(
+            Article.objects.order_by(F('headline').asc()), [
+                "Article 1",
+                "Article 2",
+                "Article 3",
+                "Article 4",
+            ],
+            attrgetter("headline")
+        )
+        self.assertQuerysetEqual(
+            Article.objects.order_by(F('headline').desc()), [
+                "Article 4",
+                "Article 3",
+                "Article 2",
+                "Article 1",
+            ],
+            attrgetter("headline")
+        )
+
+    def test_order_by_f_expression_duplicates(self):
+        """
+        A column may only be included once (the first occurrence) so we check
+        to ensure there are no duplicates by inspecting the SQL.
+        """
+        qs = Article.objects.order_by(F('headline').asc(), F('headline').desc())
+        sql = str(qs.query).upper()
+        fragment = sql[sql.find('ORDER BY'):]
+        self.assertEqual(fragment.count('HEADLINE'), 1)
+        self.assertQuerysetEqual(
+            qs, [
+                "Article 1",
+                "Article 2",
+                "Article 3",
+                "Article 4",
+            ],
+            attrgetter("headline")
+        )
+        qs = Article.objects.order_by(F('headline').desc(), F('headline').asc())
+        sql = str(qs.query).upper()
+        fragment = sql[sql.find('ORDER BY'):]
+        self.assertEqual(fragment.count('HEADLINE'), 1)
+        self.assertQuerysetEqual(
+            qs, [
+                "Article 4",
+                "Article 3",
+                "Article 2",
+                "Article 1",
+            ],
+            attrgetter("headline")
+        )