python data_error ai_generated true

AssertionError: assert '' == 'hello\n' + 其中 '' = capsys.readouterr().out

AssertionError: assert '' == 'hello\n' + where '' = capsys.readouterr().out

ID: python/pytest-capsys-not-captured

其他格式: JSON · Markdown 中文 · English

80%修复率

86%置信度

0证据数

2024-11-27首次发现

版本兼容性

版本	状态	引入	弃用	备注
3.x	active	—	—	—

根因分析

输出写入了日志处理器、子进程或 C 层文件描述符，这些 capsys 都无法捕获。capsys 仅捕获 Python 层的 sys.stdout/stderr 写入。

English

Output was written to a logging handler, a subprocess, or a C-level fd, none of which capsys captures. capsys only captures Python-level sys.stdout/stderr writes.

generic

解决方案

92% 成功率

def test_cli(capfd):
    import subprocess, sys
    subprocess.run([sys.executable, "-c", "print('hello')"])
    out, err = capfd.readouterr()
    assert out == "hello\n"

94% 成功率

import logging

def test_log(caplog):
    with caplog.at_level(logging.INFO):
        logging.getLogger("app").info("hello")
    assert "hello" in caplog.text

无效尝试

常见但无效的做法:

80% 失败
Each call drains the buffer; repeated calls return empty strings after the first.
70% 失败
That disables capture entirely; the assertion still sees nothing.