anchor.diff:            compileCss('@color1: red; body { color: @color1; }', pretty: false),
             'body { color: red; }');
       });
  -    test('less var', () {
  +    test('less_@', () {
         String css = 'body{opacity:1}';
         expect(compileCss(css), compileCss(css, polyfill: false));
         css = '@color1: red; body { color: @color1; }';
         expect(compileCss(css), isNot(compileCss(css, polyfill: false)));
       });
  +
  +    test('less_var', () {
  +      final input = '''
  +@color-background: red;
  +@color-foreground: blue;
  +.test {
  +  background-color: var(color-background);
  +  color: var(color-foreground);
  +}
  +''';
  +      final generated = '''
  +var-color-background: #f00;
  +var-color-foreground: #00f;
  +
  +.test {
  +  background-color: var(color-background);
  +  color: var(color-foreground);
  +}''';
  +      checkCompile(input, generated, pretty: true);
  +    });
     });
     //YachtTransformer transformer;
     group('csslib_exp', () {
  
positive.code: 
        expect(printStyleSheet(sheet, pretty: false),
            '.red,.blue { color: red; } .blue { width: 0; }');
      });
  
      test('scss_media_query_var_and_extend', () {
  
negative.code: body {
  color: @color1;
  }''';
  
        final generated = 'body { color: red; }';
        final generatedPretty = '''
  body {
    color: #f00;
  }''';
        checkPolyfill(css, generated); // the color is 'red'
        checkPrettyPolyfill(css, generatedPretty); // the color is '#f00';
      });
  
      test('simple_less_rule', () {
        // not working
        String css = '''
  