anchor.diff:        return;
       }
   
  -    //TODO vector
  +    if (type == EvaluationType.VECTOR) {
  +      //TODO vector
  +    }
     }
   
     /// Test the constructors of expressions.
  
positive.code:   }
  
    void defFuncRealEval() {
      throw new UnimplementedError();
    }
  
    void defFuncIntervalEval() {
  
negative.code:   get testFunctions => {
      'Expression Creation [REAL]': simpleRealCreation,
      'Expression Creation [INTERVAL]': simpleIntervalCreation,
      //'Expression Creation [VECTOR]': simpleVectorCreation,
      'Binary Op Convenience Creation': convenienceBinaryCreation,
      'Unary Op Convenience Creation': convenienceUnaryCreation,
      'Operator simplification': baseOperatorSimplification,
      'Operator differentiation': baseOperatorSimplification,
      'Simple evaluation [REAL]': simpleRealEval,
      'Simple evaluation [INTERVAL]': simpleIntervalEval,
      //'Simple evaluation [VECTOR]': simpleVectorEval,
      'Default Function Creation': defFuncCreation,
      'Default Function simplification': defFuncSimplification,
      'Default Function differentiation': defFuncDifferentiation,
      'Default Function evaluation [REAL]': defFuncRealEval,
      'Default Function evaluation [INTERVAL]': defFuncIntervalEval,
      //'Default Function evaluation [VECTOR]': defFuncVectorEval,
      /*
      'Custom Function Creation': cusFuncCreation,
      'Custom Function simplification': cusFuncSimplification,
      'Custom Function differentiation': cusFuncDifferentiation,
  