index := NewIndex()

	// test update
	index.Insert(wi1)
	index.Insert(wi2)
	index.Insert(wi3)
	index.Insert(wi4)

	// test search by service selector
	actual := FindAllInIndex(index, ByServiceSelector(selector.Namespace, labels.Instance{"app": "wle"}))
	want := []*model.WorkloadInstance{wi1, wi2}

	assert.Equal(t, len(want), len(actual))

	got := map[string]*model.WorkloadInstance{}