@Test
  public void testRecursiveSort3() throws Exception {

    int a[] = new int[5];
    selectionSort.recursiveSort(a);
    assertEquals("[0,0,0,0,0]", ArrayHelper.arrayAsString(a));
  }
  @Test
  public void testRecursiveSort4() throws Exception {

    int a[] = {1, 5, 2, 7, 3};
    selectionSort.recursiveSort(a);
    assertEquals("[1,2,3,5,7]", ArrayHelper.arrayAsString(a));
  }
  @Test
  public void testRecursiveSort1() throws Exception {

    int a[] = null;
    selectionSort.recursiveSort(a);
    assertNull(a);
  }