### Question:
CSSFileWrapper implements CssFile { public boolean add(final String selector, final Map<String, String> props) { throw new UnsupportedOperationException(); } CSSFileWrapper(final CssFile css, final boolean b); boolean add(final String selector, final Map<String, String> props); List<CssRule> get(Tag t); boolean isPersistent(); void isPersistent(final boolean b);  }### Answer:
@Test(expected=UnsupportedOperationException.class) public void testadd() { w.add("", null); }