在单元测试中模拟RestTemplate＃postForObject

Question

给定一个类EncoderService，它具有以下createNewStream方法和方法中使用的一堆常量，如何使用mockito为{{createNewStream编写单元测试1}}方法：

public ResponseEntity<Object> createNewStream(Long channelId) {
    String url = IP + VERSION + serverName + VHOSTS + vhostName + APP_NAME + appName + STREAM_FILES;

    HttpHeaders headers = new HttpHeaders();
    headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON_UTF8));
    headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
    headers.setAcceptCharset(Arrays.asList(Charset.forName(UTF_8)));

    RestTemplate restTemplate = new RestTemplate();

    String udp = "udp://" + "localhost" + ":" + "1935";
    Map<String, String> map = new HashMap<>();
    map.put("name", STREAMS + appName + channelId);
    map.put("serverName", serverName);
    map.put("uri", udp);
    HttpEntity<Map<String, String>> request = new HttpEntity<>(map, headers);

    HttpStatus statusCode = null;
    try {
        ResponseEntity<Object> response = restTemplate.postForEntity(url, request, Object.class);
        statusCode = response.getStatusCode();
        map.put(MESSAGE, "successful");
        return new ResponseEntity<>(map, statusCode);
    } catch (HttpStatusCodeException e) {
        map.put(MESSAGE, e.getMessage());
        return new ResponseEntity<>(map, HttpStatus.BAD_REQUEST);
    }
}