return increment ? div + signum : div;
  }

  /**
   * Returns {@code x mod m}, a non-negative value less than {@code m}. This differs from {@code x %
   * m}, which might be negative.
   *
   * <p>For example:
   *
   * <pre>{@code
   * mod(7, 4) == 3
   * mod(-7, 4) == 1
   * mod(-1, 4) == 3
   * mod(-8, 4) == 0
   * mod(8, 4) == 0
   * }</pre>
   *
   * @throws ArithmeticException if {@code m <= 0}

    return increment ? div + signum : div;
  }

  /**
   * Returns {@code x mod m}, a non-negative value less than {@code m}. This differs from {@code x %
   * m}, which might be negative.
   *
   * <p>For example:
   *
   * <pre>{@code
   * mod(7, 4) == 3
   * mod(-7, 4) == 1
   * mod(-1, 4) == 3
   * mod(-8, 4) == 0
   * mod(8, 4) == 0
   * }</pre>
   *
   * @throws ArithmeticException if {@code m <= 0}

  }

  @GwtIncompatible // NavigableSet
  public void testUnmodifiableNavigableSet() {
    TreeSet<Integer> mod = Sets.newTreeSet();
    mod.add(1);
    mod.add(2);
    mod.add(3);

    NavigableSet<Integer> unmod = unmodifiableNavigableSet(mod);

    /* Unmodifiable is a view. */
    mod.add(4);
    assertTrue(unmod.contains(4));
    assertTrue(unmod.descendingSet().contains(4));

  }

  public void testUnmodifiableMultimapIsView() {
    Multimap<String, Integer> mod = HashMultimap.create();
    Multimap<String, Integer> unmod = Multimaps.unmodifiableMultimap(mod);
    assertEquals(mod, unmod);
    mod.put("foo", 1);
    assertTrue(unmod.containsEntry("foo", 1));
    assertEquals(mod, unmod);
  }

  @SuppressWarnings("unchecked")
  public void testUnmodifiableMultimapEntries() {

  }

  @SuppressWarnings("deprecation")
  public void testUnmodifiableMultisetShortCircuit() {
    Multiset<String> mod = HashMultiset.create();
    Multiset<String> unmod = Multisets.unmodifiableMultiset(mod);
    assertNotSame(mod, unmod);
    assertSame(unmod, Multisets.unmodifiableMultiset(unmod));
    ImmutableMultiset<String> immutable = ImmutableMultiset.of("a", "a", "b", "a");

  @GwtIncompatible // NavigableMap
  public void testUnmodifiableNavigableMap() {
    TreeMap<Integer, String> mod = Maps.newTreeMap();
    mod.put(1, "one");
    mod.put(2, "two");
    mod.put(3, "three");

    NavigableMap<Integer, String> unmod = unmodifiableNavigableMap(mod);

    /* unmod is a view. */
    mod.put(4, "four");
    assertEquals("four", unmod.get(4));

  @GwtIncompatible // NavigableMap
  public void testUnmodifiableNavigableMap() {
    TreeMap<Integer, String> mod = Maps.newTreeMap();
    mod.put(1, "one");
    mod.put(2, "two");
    mod.put(3, "three");

    NavigableMap<Integer, String> unmod = unmodifiableNavigableMap(mod);

    /* unmod is a view. */
    mod.put(4, "four");
    assertEquals("four", unmod.get(4));

      for (int m : POSITIVE_INTEGER_CANDIDATES) {
        assertEquals(valueOf(x).mod(valueOf(m)).intValue(), LongMath.mod(x, m));
      }
    }
  }

  @GwtIncompatible // TODO
  public void testIntModNegativeModulusFails() {
    for (long x : ALL_LONG_CANDIDATES) {
      for (int m : NEGATIVE_INTEGER_CANDIDATES) {
        try {
          LongMath.mod(x, m);
          fail("Expected ArithmeticException");

      for (int m : POSITIVE_INTEGER_CANDIDATES) {
        assertEquals(valueOf(x).mod(valueOf(m)).intValue(), IntMath.mod(x, m));
      }
    }
  }

  public void testModNegativeModulusFails() {
    for (int x : POSITIVE_INTEGER_CANDIDATES) {
      for (int m : NEGATIVE_INTEGER_CANDIDATES) {
        try {
          IntMath.mod(x, m);
          fail("Expected ArithmeticException");

  }

  @SuppressWarnings("deprecation")
  public void testUnmodifiableMultisetShortCircuit() {
    Multiset<String> mod = HashMultiset.create();
    Multiset<String> unmod = Multisets.unmodifiableMultiset(mod);
    assertNotSame(mod, unmod);
    assertSame(unmod, Multisets.unmodifiableMultiset(unmod));
    ImmutableMultiset<String> immutable = ImmutableMultiset.of("a", "a", "b", "a");