In this paper, we present some ideas and experiments on using microagents for testing and repairing a distributed system, whose elements may or may not have embedded BIST (Built In Self Test) and BISR (Built In Self Repair) facilities. The microagents are software modules that perform monitoring, diagnosis and repair of the faults. They form together a society whose members communicate, set goals and solve tasks. The platforms taken into consideration for mobile tester microagents include Java Micro Edition, BREW, Symbian, PalmOS, as well as more general small scale platforms. Experimental tester agents in Java 2 Micro Edition and PalmOS are also presented, a solution that ensures portability, flexibility, but also a relatively small memory footprint.