@Test
public void testProcessCss() throws Exception {

    String expectedTextWithWhitespace = "\nt {} \n";
    Reader reader = new StringReader("a {background-color: RED}" + expectedTextWithWhitespace);
    StringWriter writer = new StringWriter();
    final AddFileUriCommentProcessor processor = new AddFileUriCommentProcessor();
    Resource resource = new Resource();
    resource.setMinimize(true);
    resource.setType(ResourceType.CSS);
    resource.setUri("file://dir/file.css");
    processor.process(resource, reader, writer);
    assertTrue(writer.toString().contains(format(START_CSS_BLOCK, resource.getUri())));
    assertTrue(writer.toString().contains(format(END_CSS_BLOCK, resource.getUri())));
    assertTrue(writer.toString().contains(expectedTextWithWhitespace));
}