From 186b40de54e3b294b2ee81c87c44acf5c25b1c17 Mon Sep 17 00:00:00 2001
From: Andres Riancho <andres.riancho@gmail.com>
Date: Thu, 26 Dec 2013 13:52:03 -0300
Subject: [PATCH] All tests pass! Fixes
 https://github.com/spulec/moto/issues/72

---
 moto/core/models.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/moto/core/models.py b/moto/core/models.py
index dd1f3794..e3777741 100644
--- a/moto/core/models.py
+++ b/moto/core/models.py
@@ -25,6 +25,7 @@ class MockAWS(object):
         self.stop()
 
     def start(self):
+        self.__class__.nested_count += 1
         self.backend.reset()
 
         if not HTTPretty.is_enabled():
@@ -48,6 +49,9 @@ class MockAWS(object):
     def stop(self):
         self.__class__.nested_count -= 1
 
+        if self.__class__.nested_count < 0:
+            raise RuntimeError('Called stop() before start().')
+
         if self.__class__.nested_count == 0:
             HTTPretty.disable()