1package queue
 2
 3import (
 4	"container/heap"
 5	"testing"
 6
 7	"github.com/stretchr/testify/assert"
 8)
 9
10func TestQueue(t *testing.T) {
11	// Some items and their priorities.
12	items := map[string]int64{
13		"id0": 2,
14		"id1": 5,
15		"id2": 4,
16	}
17
18	// Create a priority queue, put the items in it, and
19	// establish the priority queue (heap) invariants.
20	pq := make(PriorityQueue, len(items))
21	i := 0
22	for value, priority := range items {
23		pq[i] = &Item{
24			value:    value,
25			priority: priority,
26			index:    i,
27		}
28		i++
29	}
30	heap.Init(&pq)
31
32	assert.Equal(t, pq.Look().value, "id0")
33
34	// Insert a new item and then modify its priority.
35	item := &Item{
36		value:    "id3",
37		priority: 3,
38	}
39	heap.Push(&pq, item)
40	pq.update(item, item.value, 1)
41	assert.Equal(t, pq.Look().value, "id3")
42
43	// Take the items out; they arrive in increasing priority order.
44	for pq.Len() > 0 {
45		_ = heap.Pop(&pq).(*Item)
46		// fmt.Println("priority", item.priority, ":", item.value)
47	}
48	assert.Nil(t, pq.Look())
49}