模拟依赖于字符串参数的url连接对象

Question

模拟世界的新手。想知道如何通过使用模拟对象(最好是模拟对象，因为我是从它开始的)来测试以下方法

public class WeatherServiceImpl implements IWeatherService {
    private static final Logger LOGGER=LoggerFactory.getLogger(WeatherServiceImpl.class);
    @Override
    public String getWeatherDataFromWeb(String cityName){
        return run(cityName);
    }
    public String run(String city){
        long threadId=Thread.currentThread().getId();
        String myId=String.format(" (Thread ID: %d)",threadId);
        LOGGER.info("    ");
        //System.out.println("n Initializing...");
        LOGGER.info("    1.============Initializing...============"+myId);
        //format the string so that all 'space' characters are replaced by '%20'
        String cityFormatted=city.replaceAll(/s+/,"%20")
        //HTTP Get Request
        String url="http://api.openweathermap.org/data/2.5/weather?q="+cityFormatted;
        URL obj=new URL(url);
        LOGGER.info("    2.>>>>>>>>>>>> OPENING Conn."+myId)
        URLConnection conn=(HttpURLConnection) obj.openConnection();
        LOGGER.info("    3.<<<<<<<<<<<< CONN. OPENED."+myId)
        //use GET
        conn.setRequestMethod("GET");
        //Get response code
        LOGGER.info("    4.---> Sending 'GET' request to URL: "+url+myId);
        int responseCode=conn.getResponseCode();
        LOGGER.info("    5.<--- Got Response Code: "+responseCode+myId);
        StringBuffer response = new StringBuffer();
        //Check for validity of responseCode
        if(responseCode==200) {
            BufferedReader inn = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String inputLine;
            while ((inputLine = inn.readLine()) != null) {
                response.append(inputLine);
            }
            inn.close();
        } else {
            response.append("ERROR:$responseCode");
        }
        //System.out.println("n Done.");
        LOGGER.info("    6.============ Done.============"+myId);
        LOGGER.info("    ");
        return response;
    }
}

这将是很好的测试方法'run'，与一些参数返回代码200，或一些参数返回错误代码。为此，我认为我需要能够为URL类(obj)定义模拟表示，但由于这直接依赖于"city"参数，因此我不确定如何使用mock将此依赖项注入URL类(obj)的实例。

Answer 1

一种方法是在新类(如某些helper类)中使用getStringURL(String s)方法，然后将该类注入到WeatherServlceImpl中。您可以模拟这个助手类，并使getStringURL()返回一个mock URL对象。一旦有了这个，就可以模拟这个URL对象上的所有方法调用。