Fix issue trekhleb#315.

Author: trekhleb

src/data-structures/priority-queue/__test__/PriorityQueue.test.js

@@ -51,14 +51,16 @@ describe('PriorityQueue', () => {
  expect(priorityQueue.poll()).toBe(5);
  });
 
- it('should be possible to change priority of internal nodes', () => {
+ it('should be possible to change priority of head node', () => {
  const priorityQueue = new PriorityQueue();
 
  priorityQueue.add(10, 1);
  priorityQueue.add(5, 2);
  priorityQueue.add(100, 0);
  priorityQueue.add(200, 0);
 
+ expect(priorityQueue.peek()).toBe(100);
+
  priorityQueue.changePriority(100, 10);
  priorityQueue.changePriority(10, 20);
 
@@ -68,14 +70,16 @@ describe('PriorityQueue', () => {
  expect(priorityQueue.poll()).toBe(10);
  });
 
- it('should be possible to change priority of head node', () => {
+ it('should be possible to change priority of internal nodes', () => {
  const priorityQueue = new PriorityQueue();
 
  priorityQueue.add(10, 1);
  priorityQueue.add(5, 2);
  priorityQueue.add(100, 0);
  priorityQueue.add(200, 0);
 
+ expect(priorityQueue.peek()).toBe(100);
+
  priorityQueue.changePriority(200, 10);
  priorityQueue.changePriority(10, 20);