shields/lib/token-pool.spec.js

'use strict'

const { expect } = require('chai')
const sinon = require('sinon')
const times = require('lodash.times')
const { Token, TokenPool } = require('./token-pool')

function expectPoolToBeExhausted(pool) {
  expect(() => {
    pool.next()
  }).to.throw(Error, /^Token pool is exhausted$/)
}

describe('The token pool', function() {
  const ids = [1, 2, 3, 4, 5]
  const batchSize = 3

  let tokenPool
  beforeEach(function() {
    // Set up.
    tokenPool = new TokenPool(batchSize)
    ids.forEach(id => tokenPool.add(id))
  })

  it('allValidTokenIds() should return the full list', function() {
    expect(tokenPool.allValidTokenIds()).to.deep.equal(ids)
  })

  it('should yield the expected tokens', function() {
    ids.forEach(id =>
      times(batchSize, () => expect(tokenPool.next().id).to.equal(id))
    )
  })

  it('should repeat when reaching the end', function() {
    ids.forEach(id =>
      times(batchSize, () => expect(tokenPool.next().id).to.equal(id))
    )
    ids.forEach(id =>
      times(batchSize, () => expect(tokenPool.next().id).to.equal(id))
    )
  })

  context('tokens are marked exhausted immediately', function() {
    it('should be exhausted', function() {
      ids.forEach(() => {
        const token = tokenPool.next()
        token.update(0, Token.nextResetNever)
      })

      expectPoolToBeExhausted(tokenPool)
    })
  })

  context('tokens are marked after the last request', function() {
    it('should be exhausted', function() {
      ids.forEach(() => {
        const token = times(batchSize, () => tokenPool.next()).pop()
        token.update(0, Token.nextResetNever)
      })

      expectPoolToBeExhausted(tokenPool)
    })
  })

  context('tokens are renewed', function() {
    it('should keep using them', function() {
      const tokensToRenew = [2, 4]
      const renewalCount = 3

      ids.forEach(id => {
        const token = times(batchSize, () => tokenPool.next()).pop()
        const usesRemaining = tokensToRenew.includes(token.id)
          ? renewalCount
          : 0
        token.update(usesRemaining, Token.nextResetNever)
      })

      tokensToRenew.forEach(id => {
        let token
        times(renewalCount, () => {
          token = tokenPool.next()
          expect(token.id).to.equal(id)
        }).pop()
        token.update(0, Token.nextResetNever)
      })

      expectPoolToBeExhausted(tokenPool)
    })
  })

  context('tokens reset', function() {
    let clock
    beforeEach(function() {
      clock = sinon.useFakeTimers()
    })
    afterEach(function() {
      clock.restore()
    })

    it('should start using them', function() {
      const tokensToReset = [2, 4]
      const futureTime = 1440

      ids.forEach(id => {
        const token = times(batchSize, () => tokenPool.next()).pop()
        const nextReset = tokensToReset.includes(token.id)
          ? futureTime
          : Token.nextResetNever
        token.update(0, nextReset)
      })

      expectPoolToBeExhausted(tokenPool)

      clock.tick(1000 * futureTime)

      tokensToReset.forEach(id => {
        const token = times(batchSize, () => tokenPool.next()).pop()
        token.update(0, Token.nextResetNever)
      })

      expectPoolToBeExhausted(tokenPool)
    })
  })
})