diff --git a/tests/test_main.py b/tests/test_main.py
index e699d3684..99688a036 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -22,3 +22,4 @@ class TestMain(TestCase):
                 sys.stdin = dev_null
                 main(['foo.txt'])
                 sys.stdin = save_stdin
+                self.assertTrue(os.path.exists('foo.txt'))