I've been doing a little future-proofing in the XPages Jakarta EE project lately and bumped against a common pitfall in my test setup: since I create a fresh Domino Testcontainer with each run, diagnostic information like the XPages log files are destroyed at the end of each test-suite execution.
This is a companion discussion topic for the original entry at https://frostillic.us/blog/posts/2023/3/28/quick-tip-stashing-log-files-from-domino-testcontainers