如何单独测试Util类依赖于其他Util类方法？

Question

I have a util class which takes String jwtToken and Key key and decodes the jwt using io.jsonwebtoken.jwts.

However, I am not able to test this. The reason is, I am not able to mock the public key and pass to the method. So, the method breaks at Jwts.parser().serSigningKey(key)...

I tried mocking the Public key but that too did not work as I am passing mock data to real function and get UnSupportedJwtException.

One way I can think of is to move the Util that converts String to Key into Util helper for test and use it and pass the converted key into the method. This works however, I do not think it is the right way to approach the problem.

       Claims claims = null;

       try {
           claims = Jwts.parser().setSigningKey(key).parseClaimsJws(jwtToken).getBody();
       } catch (UnsupportedJwtException | MalformedJwtException | ExpiredJwtException
               | IllegalArgumentException ex) {
           LOGGER.error("Error in JWT/JWS validation", ex);
       }
       LOGGER.debug("Return Claims: ", claims);
       return claims;
   } ```

Answer 1

You can extract Jwts.parser() as separate field of your class instead of invoking this factory method directly in your method. Then you will be able to replace this object with mock