### Question:
AsyncHttpClientCallFactory implements Call.Factory { AsyncHttpClient getHttpClient() { return httpClientSupplier.get(); }  @Override Call newCall(Request request);  }### Answer:
@Test(expectedExceptions = NullPointerException.class, expectedExceptionsMessageRegExp = "httpClientSupplier is marked non-null but is null") void shouldThrowISEIfHttpClientIsNotDefined() { val factory = AsyncHttpClientCallFactory.builder() .build(); val httpClient = factory.getHttpClient(); assertNull(httpClient); }