add NoteManager and NoteQuerySet, and basic tests

notes/managers.py

@@ -1,9 +1,32 @@
 from django.db.models import Manager
+from django.db.models.query import QuerySet
+
+
+class NoteQuerySet(QuerySet):
+
+    def _ordered_by_field(self, field, reverse=False):
+        return self.order_by(   '%s%s' % (  "-" if reverse else "",
+                                            field
+                                        )
+                            )
+
+    def by_date(self, reverse=False):
+        return self._ordered_by_field('created_date', reverse=reverse)
+
+    def by_time(self, reverse=False):
+        return self._ordered_by_field('created_time', reverse=reverse)
 
 class NoteManager(Manager):
 
-    def by_date(self):
-        return self.get_queryset().order_by('created_date')
+    def get_queryset(self):
+        return NoteQuerySet(self.model)
+
+    get_query_set = get_queryset
+
+    def by_date(self, **kwargs):
+        return self.get_queryset().by_date(**kwargs)
+
+    def by_time(self, **kwargs):
+        return self.get_queryset().by_time(**kwargs)
+
 
-    def by_time(self):
-        return self.get_queryset().order_by('created_time')