warn when logging fails

[gaborbernat]

def func():
    logging.error("%s" , "a", "b")

def test_func():
    func()

Now an expectation will be thrown and written on the output... but no warning is thrown... so the test run can't be marked as failed. 🤔

[RonnyPfannschmidt]

this is the logging default behaviour

>>> import logging
>>> logging.error("%s" , "a", "b")
--- Logging error ---
Traceback (most recent call last):
  File "/usr/lib64/python3.7/logging/__init__.py", line 1025, in emit
    msg = self.format(record)
  File "/usr/lib64/python3.7/logging/__init__.py", line 869, in format
    return fmt.format(record)
  File "/usr/lib64/python3.7/logging/__init__.py", line 608, in format
    record.message = record.getMessage()
  File "/usr/lib64/python3.7/logging/__init__.py", line 369, in getMessage
    msg = msg % self.args
TypeError: not all arguments converted during string formatting
Call stack:
  File "<stdin>", line 1, in <module>
Message: '%s'
Arguments: ('a', 'b')
>>> 

so we need a more out of band handling for logging errors

[CarycaKatarzyna]

As far as I can see the logging.error is not shown if test is passed. But if test fails Captured stderr call is printed and looks like default behaviour presented by @RonnyPfannschmidt. How exactly should the expected result look like?

[RonnyPfannschmidt]

This is the expected result for wrong calls to logging

It should how alway fail the test