### Question:
TextUtils { public static String joinDelimited(Iterable<?> elements, char delimiter) { return doJoinDelimited(elements, formatForDelimiter(delimiter)); } private  TextUtils(); static String[] parseDelimited(String delimited, char delimiter); static String[] parsePMMLDelimited(String delimited); static String joinDelimited(Iterable<?> elements, char delimiter); static String joinPMMLDelimited(Iterable<?> elements); static String joinPMMLDelimitedNumbers(Iterable<? extends Number> elements); static String[] parseJSONArray(String json); static String joinJSON(Iterable<?> elements); static T readJSON(String json, Class<T> clazz); static T convertViaJSON(Object value, Class<T> clazz);  }### Answer:
@Test public void testJoinDelimited() { assertEquals("1,2,3", TextUtils.joinDelimited(Arrays.asList("1", "2", "3"), ',')); assertEquals("\"a,b\"", TextUtils.joinDelimited(Arrays.asList("a,b"), ',')); assertEquals("\"\"\"a\"\"\"", TextUtils.joinDelimited(Arrays.asList("\"a\""), ',')); assertEquals("1 2 3", TextUtils.joinDelimited(Arrays.asList("1", "2", "3"), ' ')); assertEquals("\"1 \" \"2 \" 3", TextUtils.joinDelimited(Arrays.asList("1 ", "2 ", "3"), ' ')); assertEquals("\"\"\"a\"\"\"", TextUtils.joinDelimited(Arrays.asList("\"a\""), ' ')); assertEquals("\"\"\"\" \"\"\"\"\"\"", TextUtils.joinDelimited(Arrays.asList("\"", "\"\""), ' ')); assertEquals("", TextUtils.joinDelimited(Collections.emptyList(), '\t')); }