code: protected boolean isAllowed(final Class<?> candidate) {
          return isNotAbstract(candidate) && isNotStatic(candidate) && isPublic(candidate) && isNotIgnored(candidate);
      }
docs: Verifies, if the given {@code candidate} is allowed. If this method return {@code false} the candidate will be
  removed from the list of children returned by {@link #getChildren(org.junit.runners.model.TestClass)}.
  
  Note: Clients may override this method to provide custom filtering.
  
  @param candidate the candidate to verify
  @return a boolean value