docs: public void addError(Throwable error) {
          if (error == null) {
              throw new NullPointerException("Error cannot be null");
          }
          if (error instanceof AssumptionViolatedException) {
              AssertionError e = new AssertionError(error.getMessage());
              e.initCause(error);
              errors.add(e);
          } else {
              errors.add(error);
          }
      }