CSSFileWrapper implements CssFile { public boolean isPersistent() { return persistent; } 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);  }
@Test(expected=UnsupportedOperationException.class) public void testisPersistent() { w.isPersistent(false); }