@Test
 public void testHash() {
   MutableRoaringBitmap rbm1 = new MutableRoaringBitmap();
   rbm1.add(17);
   MutableRoaringBitmap rbm2 = new MutableRoaringBitmap();
   rbm2.add(17);
   Assert.assertTrue(rbm1.hashCode() == rbm2.hashCode());
   rbm2 = rbm1.clone();
   Assert.assertTrue(rbm1.hashCode() == rbm2.hashCode());
 }
  public void rTest(final int N) {
    System.out.println("rtest N=" + N);
    for (int gap = 1; gap <= 65536; gap *= 2) {
      final BitSet bs1 = new BitSet();
      final MutableRoaringBitmap rb1 = new MutableRoaringBitmap();
      for (int x = 0; x <= N; x += gap) {
        bs1.set(x);
        rb1.add(x);
      }
      if (bs1.cardinality() != rb1.getCardinality()) throw new RuntimeException("different card");
      if (!equals(bs1, rb1)) throw new RuntimeException("basic  bug");
      for (int offset = 1; offset <= gap; offset *= 2) {
        final BitSet bs2 = new BitSet();
        final MutableRoaringBitmap rb2 = new MutableRoaringBitmap();
        for (int x = 0; x <= N; x += gap) {
          bs2.set(x + offset);
          rb2.add(x + offset);
        }
        if (bs2.cardinality() != rb2.getCardinality()) throw new RuntimeException("different card");
        if (!equals(bs2, rb2)) throw new RuntimeException("basic  bug");

        BitSet clonebs1;
        // testing AND
        clonebs1 = (BitSet) bs1.clone();
        clonebs1.and(bs2);
        if (!equals(clonebs1, MutableRoaringBitmap.and(rb1, rb2)))
          throw new RuntimeException("bug and");
        {
          final MutableRoaringBitmap t = rb1.clone();
          t.and(rb2);
          if (!equals(clonebs1, t)) throw new RuntimeException("bug inplace and");
          if (!t.equals(MutableRoaringBitmap.and(rb1, rb2))) {
            System.out.println(
                t.highLowContainer.getContainerAtIndex(0).getClass().getCanonicalName());
            System.out.println(
                MutableRoaringBitmap.and(rb1, rb2)
                    .highLowContainer
                    .getContainerAtIndex(0)
                    .getClass()
                    .getCanonicalName());

            throw new RuntimeException("bug inplace and");
          }
        }

        // testing OR
        clonebs1 = (BitSet) bs1.clone();
        clonebs1.or(bs2);

        if (!equals(clonebs1, MutableRoaringBitmap.or(rb1, rb2)))
          throw new RuntimeException("bug or");
        {
          final MutableRoaringBitmap t = rb1.clone();
          t.or(rb2);
          if (!equals(clonebs1, t)) throw new RuntimeException("bug or");
          if (!t.equals(MutableRoaringBitmap.or(rb1, rb2))) throw new RuntimeException("bug or");
          if (!t.toString().equals(MutableRoaringBitmap.or(rb1, rb2).toString()))
            throw new RuntimeException("bug or");
        }
        // testing XOR
        clonebs1 = (BitSet) bs1.clone();
        clonebs1.xor(bs2);
        if (!equals(clonebs1, MutableRoaringBitmap.xor(rb1, rb2))) {
          throw new RuntimeException("bug xor");
        }
        {
          final MutableRoaringBitmap t = rb1.clone();
          t.xor(rb2);
          if (!equals(clonebs1, t)) throw new RuntimeException("bug xor");

          if (!t.equals(MutableRoaringBitmap.xor(rb1, rb2))) {
            System.out.println(t);
            System.out.println(MutableRoaringBitmap.xor(rb1, rb2));
            System.out.println(
                Arrays.equals(t.toArray(), MutableRoaringBitmap.xor(rb1, rb2).toArray()));
            throw new RuntimeException("bug xor");
          }
        }
        // testing NOTAND
        clonebs1 = (BitSet) bs1.clone();
        clonebs1.andNot(bs2);
        if (!equals(clonebs1, MutableRoaringBitmap.andNot(rb1, rb2))) {
          throw new RuntimeException("bug andnot");
        }
        clonebs1 = (BitSet) bs2.clone();
        clonebs1.andNot(bs1);
        if (!equals(clonebs1, MutableRoaringBitmap.andNot(rb2, rb1))) {
          throw new RuntimeException("bug andnot");
        }
        {
          final MutableRoaringBitmap t = rb2.clone();
          t.andNot(rb1);
          if (!equals(clonebs1, t)) {
            throw new RuntimeException("bug inplace andnot");
          }
          final MutableRoaringBitmap g = MutableRoaringBitmap.andNot(rb2, rb1);
          if (!equals(clonebs1, g)) {
            throw new RuntimeException("bug andnot");
          }
          if (!t.equals(g)) throw new RuntimeException("bug");
        }
        clonebs1 = (BitSet) bs1.clone();
        clonebs1.andNot(bs2);
        if (!equals(clonebs1, MutableRoaringBitmap.andNot(rb1, rb2))) {
          throw new RuntimeException("bug andnot");
        }
        {
          final MutableRoaringBitmap t = rb1.clone();
          t.andNot(rb2);
          if (!equals(clonebs1, t)) {
            throw new RuntimeException("bug andnot");
          }
          final MutableRoaringBitmap g = MutableRoaringBitmap.andNot(rb1, rb2);
          if (!equals(clonebs1, g)) {
            throw new RuntimeException("bug andnot");
          }
          if (!t.equals(g)) throw new RuntimeException("bug");
        }
      }
    }
  }