使用pytest进行单元测试时，遇到了需要测试日志输出的情况，查看了文档

https://docs.pytest.org/en/latest/how-to/capture-stdout-stderr.html

https://docs.pytest.org/en/latest/how-to/logging.html

然后试了一下，捕捉logger.info可以用caplog，获取print输出可用capsys，Demo如下：

- a.py

import logginglogger = logging.getLogger(__name__)
LOG_INFO = "I'm a teapot"
PRINT_MSG = "No thing to do."def function_with_logger(msg=None):if msg is None:msg = LOG_INFOlogger.info(msg)def function_include_print():print(PRINT_MSG)

- test_a.py

import loggingfrom a import LOG_INFO, PRINT_MSG, function_include_print, function_with_loggerdef test_logger(caplog):caplog.set_level(logging.INFO)function_with_logger()log_messages = [record.message for record in caplog.records]assert LOG_INFO in log_messagescaplog.clear()function_with_logger("foo")assert "foo" in caplog.textdef test_print(capsys):function_include_print()captured = capsys.readouterr()assert PRINT_MSG in captured.out

- 验证：

pytest test_a.py