Directives controlling parallel execution of the JGroups testsuite can be specified at two levels: as parameters to the testng ant task (in build.xml), or as attributes of the suite element in the suite definition files (found in the conf/testng directory).

At present, parallelism directives in the various suite definition files (functional.xml, udp.xml, tcp.xml, etc.) take precedence over any directives specified in testng ant tasks. In fact, the directives passed to runtest in build.xml are (incorrectly) not passed through to the testng ant task, so that parallelism is controlled solely from the suite definition files.

Making use of parallel execution of test cases when running in the QA lab leads to a higher proportion of test failures, leading to a proliferation of JIRA/bugzilla issues. Therefore it is important that we be able to turn on (turn off) parallel execution of test cases through some simple specification of system properties.