--- a/src/blockdiag/tests/test_command.py
+++ b/src/blockdiag/tests/test_command.py
@@ -16,14 +16,12 @@
 import os
 import unittest
 
-from nose.tools import nottest
 from blockdiag.command import BlockdiagApp
 from blockdiag.tests.utils import TemporaryDirectory
 
 
 class TestBlockdiagApp(unittest.TestCase):
-    @nottest
-    def test_app_cleans_up_images(self):
+    def __test_app_cleans_up_images(self):
         testdir = os.path.dirname(__file__)
         diagpath = os.path.join(testdir,
                                 'diagrams',
