title: How to write a GRPC python unittest
body: <p>We are using grpc as the RPC protocol for all our internal system. Most of the system is written in Java. </p>
  
  <p>In Java, we can use InprocessServerBuilder for unittest. However, I haven't find a similar class in Python.</p>
  
  <p>Can any one provide a sample code for how to do GRPC unittest in python? </p>