### Question:
NmeaUtil { public static Talker getTalker(String s) { if (s == null) return null; else { try { return Talker.valueOf(s); } catch (RuntimeException e) { return Talker.UNKNOWN; } } } private  NmeaUtil(); static boolean isValid(String sentence); static String getChecksum(String sentence); static String getChecksum(String sentence, boolean ignoreLeadingDollarOrExclamation); static NmeaMessage parseNmea(String line); static String insertKeyValueInTagBlock(String line, String name, String value); static String supplementWithTime(String line, long arrivalTime); static Talker getTalker(String s); static String createTagBlock(LinkedHashMap<String, String> tags); static String createNmeaLine(LinkedHashMap<String, String> tags, List<String> items);  }### Answer:
@Test public void testGetTalkerGivenNullString() { assertNull(NmeaUtil.getTalker(null)); }
@Test public void testGetTalkerGivenRealTalker() { assertEquals(Talker.AB, NmeaUtil.getTalker("AB")); }
@Test public void testGetTalkerGivenUnknownTalker() { assertEquals(Talker.UNKNOWN, NmeaUtil.getTalker("ZZ")); }
@Test public void testGetTalkerDescription() { assertEquals("Independent AIS Base Station", NmeaUtil.getTalker("AB").getDescription()); }