diff --git a/Lib/test/test_mmap.py b/Lib/test/test_mmap.py
index 0a177c66a2b..f7d6c6ff650 100644
--- a/Lib/test/test_mmap.py
+++ b/Lib/test/test_mmap.py
@@ -664,6 +664,7 @@ def _make_test_file(self, num_zeroes, tail):
             f.write(tail)
             f.flush()
         except (IOError, OverflowError):
+            f.close()
             raise unittest.SkipTest("filesystem does not have largefile support")
         return f