code: public static void assertNoSubscriptionErrors(String msg, EventSubscriber subscription) {
      assertNotNull("Null assert object passed in", subscription);
  
      StringBuffer buf = new StringBuffer(msg == null ? "Subscription error(s)" : msg);
      Iterator<String> i = subscription.getEventErrors().iterator();
      while (i.hasNext()) {
        buf.append(" : ");
        buf.append((String) i.next());
      }
  
      assertEquals(buf.toString(), 0, subscription.getEventErrors().size());
    }
docs: Asserts that the given Subscription has not encountered any errors while processing received
  subscription responses and received NOTIFY requests. Assertion failure output includes the
  given message text along with the encountered error(s).
  
  @param msg message text to include if the assertion fails.
  @param subscription the Subscription in question.