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

runOrder:

Defines the order the tests will be run in. Supported values are "alphabetical", "reversealphabetical", "random", "hourly" (alphabetical on even hours, reverse alphabetical on odd hours), "failedfirst", "balanced" and "filesystem". Odd/Even for hourly is determined at the time the of scanning the classpath, meaning it could change during a multi-module build. Failed first will run tests that failed on previous run first, as well as new tests for this run. Balanced is only relevant with parallel=classes, and will try to optimize the run-order of the tests to make all tests complete at the same time, reducing the overall execution time. Note that the statistics are stored in a file named .surefire-XXXXXXXXX beside pom.xml, and should not be checked into version control. The "XXXXX" is the SHA1 checksum of the entire surefire configuration, so different configurations will have different statistics files, meaning if you change any config settings you will re-run once before new statistics data can be established.

• Type: java.lang.String
• Since: 2.7
• Required: No
• Default: filesystem

What is meaning of filesystem order? the order in which files are created?

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