Expose log format to users in assertLogs

[garry-cairns]

Feature or enhancement

Proposal:

Use-case

Someone works in an organisation with a custom log formatter. They want to make assertions about logs in a particular test and would like the assertions to match the format used in the org. Currently the format is static in assertLogs.

Example usage

format = "[No.1: the larch] %(levelname)s:%(name)s:%(message)s"
formatter = logging.Formatter(format)
with self.assertLogs(formatter=formatter) as cm:
    log_foo.info("1")
    log_foobar.debug("2")
self.assertEqual(cm.output, ["[No.1: the larch] INFO:foo:1"])

Proposed change

My branch already has my proposed change and tests are passing. Since this would be my first contribution if accepted I'm raising the issue since I don't yet have a feel for what constitutes a "minor" enhancement that doesn't need an issue ref per the developer guide. Having raised this I'll create a PR as per the developer guide.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-134567: Exposes log format to users in unittest.TestCase.assertLogs #134570