func (f *fakeBackend) Run(stopCh <-chan struct{}) error {
	return nil
}

func (f *fakeBackend) Shutdown() {
	// Nothing to do here.
}

func (f *fakeBackend) String() string {
	return ""
}

func TestUnion(t *testing.T) {
	backends := []Backend{
		new(fakeBackend),
		new(fakeBackend),
		new(fakeBackend),
	}

	b := Union(backends...)

	n := 5

	var events []*auditinternal.Event

		t.Errorf("Expected length %d != %d", len(set), len(elements))
	}

	for _, e := range elements {
		if _, exist := set[e]; !exist {
			t.Errorf("%s is not in set %v", e, set)
		}
	}
}

func TestUnion(t *testing.T) {
	elements := []string{"a", "b", "c", "d"}
	elements2 := []string{"a", "b", "e"}
	want := New("a", "b", "c", "d", "e")
	for _, sets := range [][]Set[string]{
		{New(elements...), New(elements2...)},

    Multiset<String> toRemove = HashMultiset.create(Arrays.asList("a", "b", "a"));
    assertFalse(Multisets.removeOccurrences(multiset, toRemove));
    assertTrue(multiset.isEmpty());
  }

  public void testUnion() {
    Multiset<String> ms1 = HashMultiset.create(Arrays.asList("a", "b", "a"));
    Multiset<String> ms2 = HashMultiset.create(Arrays.asList("a", "b", "b", "c"));

	a.Insert("")
	if !a.Equal(b) {
		t.Errorf("Expected to be equal: %v vs %v", a, b)
	}

	a.Delete("")
	if a.Equal(b) {
		t.Errorf("Expected to be not-equal: %v vs %v", a, b)
	}
}

func TestUnion(t *testing.T) {
	tests := []struct {
		s1       sets.Set[string]
		s2       sets.Set[string]
		expected sets.Set[string]
	}{
		{
			sets.New("1", "2", "3", "4"),
			sets.New("3", "4", "5", "6"),