diff --git a/testing/test_assertrewrite.py b/testing/test_assertrewrite.py
index 02270e157..78a5f2bae 100644
--- a/testing/test_assertrewrite.py
+++ b/testing/test_assertrewrite.py
@@ -66,7 +66,7 @@ class TestAssertionRewrite(object):
         s = """'Doc string'\nother = stuff"""
         m = rewrite(s)
         # Module docstrings in 3.7 are part of Module node, it's not in the body
-        # so we remove it so the following body items have the same indexes on 
+        # so we remove it so the following body items have the same indexes on
         # all Python versions
         if sys.version_info < (3, 7):
             assert isinstance(m.body[0], ast.Expr)