propagate env to each test run
delete output file so severe errors will be seen as failures since output file is missing
do not install artifacts files which are NOT gems, i.e. could be the embedded jar of the gem
added set of gem-homes as config to allow control over the different location where gems are installed
give preference to set jruby-version via property or plugin config
build the embedded jar during test phase so any ruby test plugin will see that jar