title: Inject TypeORM repository into NestJS service for mock data testing
body: <p>There's a longish discussion about how to do this in this <a href="https://github.com/nestjs/nest/issues/363" rel="noreferrer">issue</a>.</p>
  
  <p>I've experimented with a number of the proposed solutions but I'm not having much luck.</p>
  
  <p>Could anyone provide a concrete example of how to test a service with an injected repository and mock data?</p>