How to rewrite switch/case code with junit 4 to junit 5 or testng

I have the code:

Result result = null;
    for(int i = 1; i <= setOfConfiguration; i++){

        switch(typeOfAgreement){
                case "GUS":
                    result = JUnitCore.runClasses(first.class); break;
                case "MUS":
                    result = JUnitCore.runClasses(second.class); break;
                case "DUS":
                    result = JUnitCore.runClasses(third.class); break;
        }
      }

How to rewrite switch/case code with junit 4 to junit 5 or testng