Reader reader,
final FunctionResolver functionResolverMock) {
CSSParserFactory factory = CSSParserFactory.getDefaultInstance();
CSSParser parser = factory.createStrictParser();
StyleSheet styleSheet = parser.parseStyleSheet(reader, null);
StylingFactory stylingFactory = StylingFactory.getDefaultInstance();
CompilerConfiguration configuration =
stylingFactory.createCompilerConfiguration();
configuration.setSource(StyleSheetSource.THEME);