public Optional<String> removeStreamThread() {
        return removeStreamThread(Long.MAX_VALUE);
    }
@Test
    public void shouldNotRemoveThreadWhenNotRunning() {
        prepareStreams();
        prepareStreamThread(streamThreadOne, 1);
        props.put(StreamsConfig.NUM_STREAM_THREADS_CONFIG, 1);
        try (final KafkaStreams streams =
                     new KafkaStreams(getBuilderWithSource().build(), props, supplier, time)) {
            assertThat(streams.removeStreamThread(), equalTo(Optional.empty()));
            assertThat(streams.threads.size(), equalTo(1));
        }
    }