In this paper, we pursue our works on generic modeling and conformance testing of component-based systems. Here, we extend our theory of conformance testing to the testing of component-based systems. We first show that testing a global system can be done by testing its components thanks to the projection of global behaviors onto local ones. Secondly, based on our projection techniques, we define a framework to build adequate test purposes automatically for testing components in the context of the global system where they are plugged in. The underlying idea is to identify from any trace tr of the global system, the trace of any component involved in tr. Those projected traces can be then seen as test cases that should be tested on individual components.