The add_log/ log reporting isn't currently used but probably should be.  JUnit lets you capture the log messages from a given test, so that you can view them in for example jenkins.  That's quite handy if you have a lot of regressions - you don't have to go searching in a results directory to see logs - they are right there in Jenkins.

In other instances I've had problems were if a simulation generates a large log, eventually Jenkins will crash, so I preemptively top/tail the log files to stop them getting too large.

You can also add a failure signature to the log as a separate text field and the xunit_reporter can handle that too (again not yet hooked up)

i wanted to get the basic functionality in then build upon it, rather than dropping everything in at once.