docs: protected void validateZeroArgConstructor(List<Throwable> errors) {
          if (!getTestClass().isANonStaticInnerClass()
                  && hasOneConstructor()
                  && (getTestClass().getOnlyConstructor().getParameterTypes().length != 0)) {
              String gripe = "Test class should have exactly one public zero-argument constructor";
              errors.add(new Exception(gripe));
          }
      }