Closing a file with different closefd modes fails

[mrbean-bremen]

This is basically code taken from tempfile (found this while working on the dynamic patcher):

def test_closing_file_with_different_close_mode(self):
    filename = self.make_path('test.txt')
    fd = self.os.open(filename, os.O_CREAT | os.O_RDWR | os.O_BINARY, 0o600)
    with self.open(fd, 'wb', closefd=False) as fp:
        fp.write(b'test')
    self.os.close(fd)
    self.assertTrue(fp.closed)

This fails in the fake implemenation (self.os / self.open being the fake implementation in this case) because the fd is not closed in the last close() call as it should have been.