[https://wiki.onap.org/display/DW/Control+Loop+Simulation+and+Injection+of+Messages+Overview]

 
For example:

1. Using feature: "features enable controlloop-utils" for simulation of other network components.
2. Using the telemetry APIs to inject ONSETs, etc .. (no need to get in low level details, just the basics).
3. In Junits, overview or pointers to the code on how to test it.