diff --git a/IPython/nbconvert/tests/test_nbconvertapp.py b/IPython/nbconvert/tests/test_nbconvertapp.py
index 23b446e..2e83757 100644
--- a/IPython/nbconvert/tests/test_nbconvertapp.py
+++ b/IPython/nbconvert/tests/test_nbconvertapp.py
@@ -23,7 +23,7 @@ from IPython.utils import py3compat
 # Constants
 #-----------------------------------------------------------------------------
 
-#Define ipython commandline name
+# Define ipython commandline name
 if py3compat.PY3:
     IPYTHON = 'ipython3'
 else: