diff --git a/Lib/test/test_mmap.py b/Lib/test/test_mmap.py
index 26dbc4a..ea9c4ee 100644
--- a/Lib/test/test_mmap.py
+++ b/Lib/test/test_mmap.py
@@ -221,11 +221,12 @@
         verify(m[:] == 'c'*mapsize,
                "Write-through memory map memory not updated properly.")
         m.flush()
-        del m, f
+        m.close()
+        f.close()
         f = open(TESTFN, 'rb')
         stuff = f.read()
         f.close()
-        verify(open(TESTFN, 'rb').read() == 'c'*mapsize,
+        verify(stuff == 'c'*mapsize,
                "Write-through memory map data file not updated properly.")
 
         print "  Opening mmap with access=ACCESS_COPY"