### Question:
ConstrettoUtils { public static String asCsv(String[] arr) { StringBuffer tagcsv = new StringBuffer(); for (String tag : arr) { if (tagcsv.length() > 0) { tagcsv.append(","); } tagcsv.append(tag); } return tagcsv.toString(); }  static String asCsv(String[] arr); static List<String> fromCSV(String csv); static boolean isEmpty(String string); static String substringBetween(String str, String open, String close); static String substringAfter(String str, String separator); static Locale toLocale(String str); @SuppressWarnings("unchecked") static void mergePropertiesIntoMap(Properties props, Map map);  }### Answer:
@Test public void testAsCsv() throws Exception { final String csvText = ConstrettoUtils.asCsv(new String[]{VALUE_ONE, VALUE_TWO}); assertEquals(VALUE_ONE + "," + VALUE_TWO, csvText); }