@Test
public void testProxyProperties_throwsExceptionWhenMissingProxyAddress() {

  HadoopConfigurationProperty<String> gcsProxyUsername =
      new HadoopConfigurationProperty<>(
          GCS_CONFIG_PREFIX + PROXY_USERNAME_SUFFIX.getKey(), "proxy-user");
  HadoopConfigurationProperty<String> gcsProxyPassword =
      new HadoopConfigurationProperty<>(
          GCS_CONFIG_PREFIX + PROXY_PASSWORD_SUFFIX.getKey(), "proxy-pass");
  Configuration config = new Configuration();
  config.set(gcsProxyUsername.getKey(), gcsProxyUsername.getDefault());
  config.set(gcsProxyPassword.getKey(), gcsProxyPassword.getDefault());
  GoogleCloudStorageOptions.Builder optionsBuilder =
      GoogleHadoopFileSystemConfiguration.getGcsOptionsBuilder(config);
  assertThrows(IllegalArgumentException.class, optionsBuilder::build);
}