final Exception[] exceptionHolder = new Exception[1];

        Thread thread = new Thread(() -> {
            try {
                clientHolder[0] = new CrawlerEngineClient();
            } catch (Exception e) {
                exceptionHolder[0] = e;
            }
        });

        thread.start();
        thread.join();

        assertNull(exceptionHolder[0]);
        assertNotNull(clientHolder[0]);