This is on Windows XP SP2. Using Python 2.7.1 and 2.7.2.

While executing the unit tests of the PySerial package, version 2.5 (http://pypi.python.org/pypi/pyserial) one of the tests fails when using the C version of the io module ("io"), but pass if the pure Python version is used ("_pyio.py").

The specific test case in question is: test_iolib.py. When executed like:

    > python test_iolib.py loop://

the test fails with the following traceback:

----
Traceback (most recent call last):
  File "C:\pyserial-2.5\test\test_iolib.py", line 68, in test_hello_raw

    self.failUnlessEqual(hello, unicode("hello\n"))
AssertionError: u'<memory at 0x00C5D940>' != u'hello\n'
----

And Windows shows a crash report dialog, with the following information:

----
AppName: python.exe	 AppVer: 0.0.0.0	 ModName: python27.dll
ModVer: 2.7.2150.1013	 Offset: 00089f57

Exception Information
Code: 0xc0000005	Flags: 0x00000000
Record: 0x0000000000000000	Address: 0x000000001e089f57
----

As said above, if in the said test case, instead of "import io" one does "import _pyio as io", the crash does not happens, and the test succeeds.