private void runRenderTest(String goldenFile, String inputFile)
throws Exception {
String golden = TestUtil.readResource(getClass(), goldenFile);
CssTree.StyleSheet stylesheet = css(fromResource(inputFile));
StringBuilder sb = new StringBuilder();
CssPrettyPrinter csspp = new CssPrettyPrinter(sb);
RenderContext rc = new RenderContext(csspp);
stylesheet.render(rc);
assertEquals(golden.trim(), sb.toString().trim());
}