public static AwsClientFactory from(Map<String, String> properties) {
    String factoryImpl =
        PropertyUtil.propertyAsString(
            properties, AwsProperties.CLIENT_FACTORY, DefaultAwsClientFactory.class.getName());
    return loadClientFactory(factoryImpl, properties);
  }
@Test
  public void testLoadCustom() {
    Map<String, String> properties = Maps.newHashMap();
    properties.put(AwsProperties.CLIENT_FACTORY, CustomFactory.class.getName());
    assertThat(AwsClientFactories.from(properties))
        .as("should load custom class")
        .isInstanceOf(CustomFactory.class);
  }