Maven Surefire plugin: what is meaning of filesystem in runOrder?

Question

I wanted to know if my integration tests will run in specific order and looked at the maven-failsafe-plugin documentation, which is

Answer 1

When you list files in a directory most tools show them in alphabetical order, but their real "default" order is implementation specific.

You can use ls -U to show that order on linux.

from a ls manpage:

-U     do not sort; list entries in directory order