Assert.isTrue(snsTestProxy != null || awsCredentialsProvider != null,
"Either snsTestProxy or awsCredentialsProvider needs to be provided");
if (messageMarshaller == null) {
messageMarshaller = new JsonMessageMarshaller();
}
if (snsTestProxy == null) {
if (awsClientConfiguration == null) {
client = new AmazonSNSClient(awsCredentialsProvider);