@Test
public void testPredefinedSignerInitialization() throws IOException {

  // Try initializing a pre-defined Signer type.
  // Should run through without an exception.
  Configuration config = new Configuration();
  // Pre-defined signer types as of AWS-SDK 1.11.563
  // AWS4SignerType, QueryStringSignerType, AWSS3V4SignerType
  config.set(CUSTOM_SIGNERS, "AWS4SignerType");
  SignerManager signerManager = new SignerManager("dontcare", null, config,
      UserGroupInformation.getCurrentUser());
  signerManager.initCustomSigners();
}