title: How to unit-test third-party library wrappers?
body: <p>Everyone tell <strong>Don't mock what you don't own</strong>. They recommend to make a wrapper for 3rd party library instead.</p>
  
  <p>But how do I test this wrapper?</p>
  
  <p>I mean, if I write unit tests for it and will mock those 3rd party interfaces to test my wrapper, nothing will change.
  If library maintainer will change its API I will face same problem - tests for mocked lib will go fine and software will fail in production environment.
  What is the advantage for reliability or testability here?</p>
  
  <p>I know there is advantage for code quality because I could exchange this library whenever I want, but it is not subject of this question.</p>
  
  <p>Thanks.</p>