Helper { public static void shuffleIntArray(int[] arr) { if (arr == null || arr.length == 0) throw new IllegalArgumentException("Array cannot be null or have zero length"); for (int i = arr.length - 1; i > 0; i--) { int index = rnd.nextInt(i + 1); int a = arr[index]; arr[index] = arr[i]; arr[i] = a; } }  static void shuffleIntArray(int[] arr); static int[] convertIntegerListToIntArray(List<Integer> listOfInts); static Point rotatePoint(Point reference, Point toRotate, int degrees); static void validateCodePointValues(int[] codePoints); static int[] constructCodePointArrayFomMinMaxValues(int minCodePoint, int maxCodePoint); static int convertStringToIntOrDefault(String str, int defaultValue); static int[] convertCodePointsToSortedIntArrayNoDuplicates(String line, String range);  }
@Test(expected = IllegalArgumentException.class) public void testShuffleIntArrayWithNullArray() throws Exception { Helper.shuffleIntArray(null); }
@Test(expected = IllegalArgumentException.class) public void testShuffleIntArrayWithEmptyArray() throws Exception { Helper.shuffleIntArray(new int[]{}); }