anchor.diff:          
           // The call under test
           var future = objectToJson(object);
  +        future.catchError((error) => registerException(error));
           
           var expectation = new Map();
           
  
positive.code:           
            // The call under test
            var future = objectToJson(list);
            
            var expectation = new List();
            expectation.add(new Map());
  
negative.code:         
          // The call under test
          var future = objectToJson(object);
          future.catchError((error) => registerException(error));
          
          var expectation = new Map();
          
  