add nested for all aliases as postgres serves nulls first when order by desc

tests/test_order_by.py

@@ -303,14 +303,16 @@ async def test_sort_order_with_aliases():
     async with database:
         al1 = await AliasTest.objects.create(name="Test4")
         al2 = await AliasTest.objects.create(name="Test2")
-        await AliasTest.objects.create(name="Test1")
-        await AliasTest.objects.create(name="Test3")
+        al3 = await AliasTest.objects.create(name="Test1")
+        al4 = await AliasTest.objects.create(name="Test3")
 
         aliases = await AliasTest.objects.order_by("-name").all()
         assert [alias.name[-1] for alias in aliases] == ["4", "3", "2", "1"]
 
         nest1 = await AliasNested.objects.create(name="Try1")
         nest2 = await AliasNested.objects.create(name="Try2")
+        nest3 = await AliasNested.objects.create(name="Try3")
+        nest4 = await AliasNested.objects.create(name="Try4")
 
         al1.nested = nest1
         await al1.update()
@@ -318,12 +320,18 @@ async def test_sort_order_with_aliases():
         al2.nested = nest2
         await al2.update()
 
+        al3.nested = nest3
+        await al3.update()
+
+        al4.nested = nest4
+        await al4.update()
+
         aliases = (
             await AliasTest.objects.select_related("nested")
             .order_by("-nested__name")
             .all()
         )
-        assert aliases[0].nested.name == "Try2"
-        assert aliases[1].nested.name == "Try1"
-        assert aliases[2].nested is None
-        assert aliases[3].nested is None
+        assert aliases[0].nested.name == "Try4"
+        assert aliases[1].nested.name == "Try3"
+        assert aliases[2].nested.name == "Try2"
+        assert aliases[3].nested.name == "Try1"