@Override
  public String toString() {
    StringBuilder sb = new StringBuilder().append("{");
    sb.append(_fixable ? "Fixable " : " Unfixable ");
    sb.append("broker failures detected: {");
    if (_failedBrokers != null) {
      _failedBrokers.forEach((key, value) -> sb.append("Broker ").append(key).append(" failed at ").append(utcDateFor(value)).append(",\t"));
      sb.setLength(sb.length() - 2);
    }
    sb.append("}}");
    return sb.toString();
  }
@Test
    public void testToString() {
        assertNotNull(new BrokerFailures().toString());
    }