test_fileinput.py 文件源码

def test_nextfile_oserror_deleting_backup(self):
        """Tests invoking FileInput.nextfile() when the attempt to delete
           the backup file would raise OSError.  This error is expected to be
           silently ignored"""

        os_unlink_orig = os.unlink
        os_unlink_replacement = UnconditionallyRaise(OSError)
        try:
            t = writeTmp(1, ["\n"])
            self.addCleanup(remove_tempfiles, t)
            with FileInput(files=[t], inplace=True) as fi:
                next(fi) # make sure the file is opened
                os.unlink = os_unlink_replacement
                fi.nextfile()
        finally:
            os.unlink = os_unlink_orig

        # sanity check to make sure that our test scenario was actually hit
        self.assertTrue(os_unlink_replacement.invoked,
                        "os.unlink() was not invoked")