old_contents: class DispatchTestService {
      returnFortyTwo () {
          return 42;
      }
  
      doubleArgument (x) {
          return 2 * x;
      }
  
      throwException () {
          throw new Error('This is a test exception thrown by LocalDispatchTest');
      }
  
      close () {
          // eslint-disable-next-line no-undef
          self.close();
      }
  }
  
  module.exports = DispatchTestService;
  
new_contents: class DispatchTestService {
      returnFortyTwo () {
          return 42;
      }
  
      doubleArgument (x) {
          return 2 * x;
      }
  
      throwException () {
          throw new Error('This is a test exception thrown by DispatchTest');
      }
  
      close () {
          // eslint-disable-next-line no-undef
          self.close();
      }
  }
  
  module.exports = DispatchTestService;
  
subject: Fix exception message