Change Test Class Path

[Johannes Ruscheinski]

Hi,

I am trying to create a new mojo based on Surefire.   This will be a timing
regression test.
In order to do  that we specify a "baselineVersion" configuration parameter.
Basically I plan on running the tests twice,  first with the normal 
configuration
and then again with the current artifact's version replaced by 
baselineVersion.   How can I update/change the class path in order to do that?
Again, I am talking about  the Java source for the surefire plugin.

Thanks!