### Question:
GroupKey { public static String getKey(String dataId, String group) { return doGetKey(dataId, group, ""); }  static String getKey(String dataId, String group); static String getKey(String dataId, String group, String datumStr); static String getKeyTenant(String dataId, String group, String tenant); static String[] parseKey(String groupKey);  }### Answer:
@Test public void testGetKeyByThreeParams() { final String actual = GroupKey.getKey(",", ",", "3"); Assert.assertEquals(",+,+3", actual); }
@Test public void testGetKeyByTwoParams() { final String actual = GroupKey.getKey("3", "'"); Assert.assertEquals("3+'", actual); }