http://buildbot.python.org/all/builders/AMD64%20FreeBSD%209.0%20dtrace%203.x/builds/1560/steps/test/logs/stdio

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FAIL: test_trailers (test.test_os.TestSendfile)
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Traceback (most recent call last):
  File "/usr/home/buildbot/python/3.x.koobs-freebsd/build/Lib/test/test_os.py", line 1962, in test_trailers
    self.assertEqual(data, b"abcde12345")
AssertionError: b'abcde\x00\x00\x00...\x00\x0012345' != b'abcde12345'
Warning -- threading._dangling was modified by test_os
test test_os failed

(I replaced a long list of \x00 with "...")

I don't understand why test_trailers() of test_os tries to copy 4096 bytes using os.sendto(), whereas the input file only contains 5 bytes.