import { CircularQueue } from '../circular_queue'

describe('Circular Queue', () => {

let queue: CircularQueue<number>

beforeEach(() => {

queue = new CircularQueue(5)

})

it('should enqueue an element', () => {

queue.enqueue(1)

expect(queue.peek()).toBe(1)

})

it('should throw an error on enqueue when queue is full', () => {

queue.enqueue(1)

queue.enqueue(2)

queue.enqueue(3)

queue.enqueue(4)

queue.enqueue(5)

expect(() => queue.enqueue(6)).toThrowError('Queue is full')

})

it('should dequeue an element', () => {

queue.enqueue(1)

queue.enqueue(2)

expect(queue.dequeue()).toBe(1)

})

it('should throw an error on dequeue when queue is empty', () => {

expect(() => queue.dequeue()).toThrowError('Queue is empty')

})

it('should peek an element', () => {

queue.enqueue(1)

queue.enqueue(2)

expect(queue.peek()).toBe(1)

})

it('should return null on peek when queue is empty', () => {

expect(queue.peek()).toBeNull()

})

it('should return true on isEmpty when queue is empty', () => {

expect(queue.isEmpty()).toBeTruthy()

})

it('should return false on isEmpty when queue is not empty', () => {

queue.enqueue(1)

expect(queue.isEmpty()).toBeFalsy()

})

it('should return the correct length', () => {

queue.enqueue(1)

queue.enqueue(2)

queue.enqueue(3)

expect(queue.length()).toBe(3)

})

})