Set<Set<Integer>> powerSet2 = powerSet(elements);
      new EqualsTester()
          .addEqualityGroup(powerSet1, powerSet2, toHashSets(powerSet1))
          .addEqualityGroup(ImmutableSet.of())
          .addEqualityGroup(ImmutableSet.of(9999999))
          .addEqualityGroup("notASet")
          .testEquals();
      assertEquals(toHashSets(powerSet1).hashCode(), powerSet1.hashCode());
    }

    new EqualsTester()
        .addEqualityGroup(BloomFilter.create(Funnels.byteArrayFunnel(), 100, 0.01))
        .addEqualityGroup(BloomFilter.create(Funnels.byteArrayFunnel(), 100, 0.02))
        .addEqualityGroup(BloomFilter.create(Funnels.byteArrayFunnel(), 200, 0.01))
        .addEqualityGroup(BloomFilter.create(Funnels.byteArrayFunnel(), 200, 0.02))
        .addEqualityGroup(BloomFilter.create(Funnels.unencodedCharsFunnel(), 100, 0.01))

    assertTrue(multimap.get(2).contains("hey you"));
  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(ImmutableMultimap.of(), ImmutableMultimap.of())
        .addEqualityGroup(ImmutableMultimap.of(1, "a"), ImmutableMultimap.of(1, "a"))
        .addEqualityGroup(
            ImmutableMultimap.of(1, "a", 2, "b"), ImmutableMultimap.of(2, "b", 1, "a"))
        .testEquals();
  }

      Set<Set<Integer>> powerSet2 = powerSet(elements);
      new EqualsTester()
          .addEqualityGroup(powerSet1, powerSet2, toHashSets(powerSet1))
          .addEqualityGroup(ImmutableSet.of())
          .addEqualityGroup(ImmutableSet.of(9999999))
          .addEqualityGroup("notASet")
          .testEquals();
      assertEquals(toHashSets(powerSet1).hashCode(), powerSet1.hashCode());
    }
  }

  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(ImmutableMultiset.of(), ImmutableMultiset.of())
        .addEqualityGroup(ImmutableMultiset.of(1), ImmutableMultiset.of(1))
        .addEqualityGroup(ImmutableMultiset.of(1, 1), ImmutableMultiset.of(1, 1))
        .addEqualityGroup(ImmutableMultiset.of(1, 2, 1), ImmutableMultiset.of(2, 1, 1))
        .testEquals();
  }

                return factory.getName()
                    + "("
                    + Joiner.on(", ").useForNull("null").join(factoryArgs)
                    + ")";
              }
            });
    tester.addEqualityGroup(instance, createInstance(factory, equalArgs));
    for (int i = 0; i < params.size(); i++) {
      List<Object> newArgs = Lists.newArrayList(args);

    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)
        .addEqualityGroup(reverse)
        .addEqualityGroup(diff2)
        .testEquals();
  }

  public void testMapDifferencePredicateTypical() {

                return factory.getName()
                    + "("
                    + Joiner.on(", ").useForNull("null").join(factoryArgs)
                    + ")";
              }
            });
    tester.addEqualityGroup(instance, createInstance(factory, equalArgs));
    for (int i = 0; i < params.size(); i++) {
      List<Object> newArgs = Lists.newArrayList(args);