title: Powermock fails tests
body: <p>I wanted to replace my JUnitRunner by Powermockrunnner (in order to further use features of Powermock that simple Mockito does not have).</p>
  
  <p>So I added the dependencies, replaced the runner in my test class, and added the @PrepareForTest annotation and, before writing any further test code, ran my existing tests to validate them.</p>
  
  <p>Of ~25 tests, 5 or 6 failed with apparently functional reasons (I mean they failed on actual failures in the run code, not on some infrastructural errors).</p>
  
  <p>In a normal state, these tests are 100% consistent and non-flaky.</p>
  
  <p>How can such a change fail fully working tests?</p>