code: private static void sanityCheck() {
          List<TestContainerFactory> factories = new ArrayList<TestContainerFactory>();
  
          Iterator<TestContainerFactory> iter = ServiceLoader.load(TestContainerFactory.class)
              .iterator();
          while (iter.hasNext()) {
              factories.add(iter.next());
          }
          if (factories.size() == 0) {
              throw new TestContainerException("No TestContainer implementation in Classpath");
          }
          else if (factories.size() > 1) {
              for (TestContainerFactory fac : factories) {
                  LOG.error("Ambiguous TestContainer:  " + fac.getClass().getName());
              }
              throw new TestContainerException("Too many TestContainer implementations in Classpath");
          }
          else {
              // good!
              return;
          }
      }
docs: Exits with an exception if Classpath not set up properly.