public void testClear()
{
TagExtractor extractor = new TagExtractor("abstract", 10);
extractor.setTag("abstract");
extractor.add("This is a sample text.");
Assert.AreEqual(extractor.buf_.ToString(), "This is a sample text.");
Assert.AreEqual(extractor.tag_, "abstract");
extractor.clear();
Assert.AreEqual(extractor.buf_.ToString(), "");
Assert.AreEqual(extractor.tag_, null);
}