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