explicit map to haxe.ds.StringMap fix fails test

[AllNamesRTaken]

Hi,
I needed a parse of a StringMap so I added it. It works in my project but the test I added to TJSON fails. Using the same tjson file in my own project parses just fine?! Any clue?
public function testParseMap(){
var map:Map<String,Int> = TJSON.parse('{"_hxcls":"haxe.ds.StringMap", "first":42}');
assertEquals(42, map.get("first"));
}

• TestParser::testParseMap()
  ERR: exception thrown : JSON Data on line 1: $nargs

Called from tjson/TJSON.hx line 65
Called from tjson/TJSON.hx line 14
Called from TestParser.hx line 156