anchor.diff:  
     test("Serialize complex Map with int", () {
       var complex = new DoubleComplex()
  -      ..list = [1, 2, 3] as List<double>
  -      ..map = {"foo": 1} as Map<String,double>;
  +      ..list = [1, 2, 3]
  +      ..map = {"foo": 1};
       var output = _jsonSerializer.toMap(complex);
       expect(output["map"], {"foo": 1});
       expect(output["list"], [1, 2, 3]);
  
positive.code: 
    test("Serialize simple Json with int", () {
      var simple = new DoubleSimple()
        ..test = 1 as double;
      var output = _jsonSerializer.encode(simple);
      expect(output, '{"test":1}');
    });
  
negative.code: 
    test("Serialize simple Map with int", () {
      var simple = new DoubleSimple()
        ..test = 1;
      var output = _jsonSerializer.toMap(simple);
      expect(output, {"test": 1});
    });
  