### Question:
TagExtractor { public void setTag(String tag){ tag_ = tag; } TagExtractor(String tag, int threshold); int count(); void clear(); void setTag(String tag); void add(String line); String closeTag();  }### Answer:
@Test public final void testSetTag() { TagExtractor extractor = new TagExtractor(null, 0); extractor.setTag(""); assertEquals(extractor.tag_, ""); extractor.setTag(null); assertEquals(extractor.tag_, null); }