AzureBlobSystemProducer implements SystemProducer { @Override public synchronized void start() { if (isStarted) { LOG.warn("Attempting to start an already started producer."); return; } String accountName = config.getAzureAccountName(systemName); String accountKey = config.getAzureAccountKey(systemName); setupAzureContainer(accountName, accountKey); LOG.info("Starting producer."); isStarted = true; } AzureBlobSystemProducer(String systemName, AzureBlobConfig config, MetricsRegistry metricsRegistry); @Override synchronized void start(); @Override synchronized void stop(); @Override synchronized void register(String source); @Override void send(String source, OutgoingMessageEnvelope messageEnvelope); @Override void flush(String source);  }
@Test public void testStart() { systemProducer.start(); verify(systemProducer).setupAzureContainer(ACCOUNT_NAME, ACCOUNT_KEY); }