From 3ee88ecf93ffaad8eb753021b1e811a27c8d513f Mon Sep 17 00:00:00 2001
From: Blake Eggleston <bdeggleston@gmail.com>
Date: Wed, 14 Aug 2013 15:48:24 -0700
Subject: [PATCH] setting counter column default instantiation value to 0 (not
 None)

---
 cqlengine/columns.py                           |  9 +++++++++
 cqlengine/tests/columns/test_counter_column.py | 13 +++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/cqlengine/columns.py b/cqlengine/columns.py
index 56221c2d..9940f1aa 100644
--- a/cqlengine/columns.py
+++ b/cqlengine/columns.py
@@ -246,9 +246,18 @@ class Integer(Column):
         return self.validate(value)
 
 
+class CounterValueManager(BaseValueManager):
+    def __init__(self, instance, column, value):
+        super(CounterValueManager, self).__init__(instance, column, value)
+        self.value = self.value or 0
+        self.previous_value = self.previous_value or 0
+
+
 class Counter(Integer):
     db_type = 'counter'
 
+    value_manager = CounterValueManager
+
     def __init__(self,
                  index=False,
                  db_field=None,
diff --git a/cqlengine/tests/columns/test_counter_column.py b/cqlengine/tests/columns/test_counter_column.py
index f92cb4f4..f8dc0096 100644
--- a/cqlengine/tests/columns/test_counter_column.py
+++ b/cqlengine/tests/columns/test_counter_column.py
@@ -59,6 +59,15 @@ class TestCounterColumn(BaseCassEngTestCase):
 
     def test_update_from_none(self):
         """ Tests that updating from None uses a create statement """
+        instance = TestCounterModel()
+        instance.counter += 1
+        instance.save()
+
+        new = TestCounterModel.get(partition=instance.partition)
+        assert new.counter == 1
+
+    def test_new_instance_defaults_to_zero(self):
+        """ Tests that instantiating a new model instance will set the counter column to zero """
+        instance = TestCounterModel()
+        assert instance.counter == 0
 
-    def test_multiple_inserts(self):
-        """ Tests inserting over existing data works as expected """