test_web_concurrency_with_concurrent_ruby_available fails on single-cpu systems

[sanvila]

Hello. When I try to build (the Debian package of) puma on a system with a single CPU, there is a test which always fails:

Errors & Failures:

  1) Failure:
TestWebConcurrencyAuto#test_web_concurrency_with_concurrent_ruby_available [test/helpers/integration.rb:235]:
Timeout waiting for server to log /PID: (\d+)\) booted in [.0-9]+s, phase: 0/

Does this mean that puma will not work properly on single-cpu systems, or maybe it just means that such test is not expected to work on such systems? The Debian package could be modified easily to skip such test based on the output of nproc, but maybe it would be better if this could be handled by the test itself.

This should be easy to reproduce by using GRUB_CMDLINE_LINUX="nr_cpus=1".

Thanks.