checkVersionsOrder(c, d);
        checkVersionsOrder(b, d);
        checkVersionsOrder(a, d);
    }

    /**
     * Test all versions are equal when starting with many leading zeroes regardless of string length
     * (related to MNG-6572 optimization)
     */
    @Test
    void testVersionEqualWithLeadingZeroes() {
        // versions with string lengths from 1 to 19

              });
      assertEquals("Counts not as expected", Ints.asList(deltas), actualCounts);
    } finally {
      pool.shutdownNow();
    }

    // Since we have access to the backing map, verify that there are no zeroes in the map
    for (AtomicInteger value : map.values()) {
      assertTrue("map should not contain a zero", value.get() != 0);
    }
  }

  private static class MutateTask implements Callable<int[]> {

   * AtomicInteger's atomic operations, with some help from ConcurrentMap's atomic operations on
   * creation and removal (including automatic removal of zeroes). If the modification of an
   * AtomicInteger results in zero, we compareAndSet the value to zero; if that succeeds, we remove
   * the entry from the Map. If another operation sees a zero in the map, it knows that the entry is

   * it is returned directly. Otherwise, a new array of size {@code minLength + padding} is
   * returned, containing the values of {@code array}, and zeroes in the remaining places.
   *
   * @param array the source array
   * @param minLength the minimum length the returned array must guarantee
   * @param padding an extra amount to "grow" the array by if growth is necessary

   * it is returned directly. Otherwise, a new array of size {@code minLength + padding} is
   * returned, containing the values of {@code array}, and zeroes in the remaining places.
   *
   * @param array the source array
   * @param minLength the minimum length the returned array must guarantee
   * @param padding an extra amount to "grow" the array by if growth is necessary

   * it is returned directly. Otherwise, a new array of size {@code minLength + padding} is
   * returned, containing the values of {@code array}, and zeroes in the remaining places.
   *
   * @param array the source array
   * @param minLength the minimum length the returned array must guarantee
   * @param padding an extra amount to "grow" the array by if growth is necessary