test_fileinput.py 文件源码

def test_readline_os_chmod_raises_OSError(self):
        """Tests invoking FileInput.readline() when os.chmod() raises OSError.
           This exception should be silently discarded."""

        os_chmod_orig = os.chmod
        os_chmod_replacement = UnconditionallyRaise(OSError)
        try:
            t = writeTmp(1, ["\n"])
            self.addCleanup(remove_tempfiles, t)
            with FileInput(files=[t], inplace=True) as fi:
                os.chmod = os_chmod_replacement
                fi.readline()
        finally:
            os.chmod = os_chmod_orig

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