hystrixjs/test/metrics/RollingNumber.spec.js

resilience module for NodeJS applications

'use strict';

const RollingNumber = require("../../lib/metrics/RollingNumber");
const RollingNumberEvent = require("../../lib/metrics/RollingNumberEvent");
const rewire = require("rewire");
const support = require("../support");

describe("RollingNumber", function () {

    it("should be initialised with default values", function () {
        const underTest = new RollingNumber();
        expect(underTest.windowLength).toBe(10000);
        expect(underTest.numberOfBuckets).toBe(10)
    });

    it("should be initialised with option values", function () {
        const underTest = new RollingNumber({timeInMillisecond: 5000, numberOfBuckets: 5});
        expect(underTest.windowLength).toBe(5000);
        expect(underTest.numberOfBuckets).toBe(5)
    });

    it("should increment a value in the latest bucket", function () {
        const underTest = new RollingNumber({windowLength: 60000, numberOfBuckets: 5});
        const lastBucket = underTest.getCurrentBucket();
        underTest.increment(RollingNumberEvent.SUCCESS);
        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(lastBucket.get(RollingNumberEvent.SUCCESS)).toBe(2);
    });

    it("should roll the last bucket", function () {
        const RollingNumberRewired = rewire("../../lib/metrics/RollingNumber");
        const underTest = new RollingNumberRewired();

        underTest.increment(RollingNumberEvent.SUCCESS);
        support.fastForwardActualTime(RollingNumberRewired, 1001);

        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(underTest.buckets.length).toBe(2);
    });

    it("should reset the window if no activity was reported for the period longer than the window itself", function () {
        const RollingNumberRewired = rewire("../../lib/metrics/RollingNumber");
        const underTest = new RollingNumberRewired({timeInMillisecond: 1000, numberOfBuckets: 2});
        underTest.increment(RollingNumberEvent.SUCCESS);
        underTest.rollWindow(Date.now());
        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(underTest.buckets.length).toBe(2);

        support.fastForwardActualTime(RollingNumberRewired, 1001);

        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(underTest.buckets.length).toBe(1);
    });


    it("should not exceed the max number of buckets", function () {
        const underTest = new RollingNumber({windowLength: 60000, numberOfBuckets: 2});
        underTest.rollWindow(new Date().getTime());
        underTest.rollWindow(new Date().getTime());
        underTest.rollWindow(new Date().getTime());
        underTest.rollWindow(new Date().getTime());
        expect(underTest.buckets.length).toBe(2);
    });

    it("should return the sum of the values from all buckets", function () {
        const RollingNumberRewired = rewire("../../lib/metrics/RollingNumber");
        const underTest = new RollingNumberRewired();

        underTest.increment(RollingNumberEvent.SUCCESS);

        support.fastForwardActualTime(RollingNumberRewired, 1500);
        underTest.increment(RollingNumberEvent.SUCCESS);
        underTest.increment(RollingNumberEvent.SUCCESS);
        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(underTest.buckets.length).toBe(2);
        expect(underTest.getRollingSum(RollingNumberEvent.SUCCESS)).toBe(4);
    });

    it("should accumulate events over time", function () {
        const RollingNumberRewired = rewire("../../lib/metrics/RollingNumber");
        const underTest = new RollingNumberRewired();

        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(underTest.getCurrentBucket().get(RollingNumberEvent.SUCCESS)).toBe(1);
        expect(underTest.getCumulativeSum(RollingNumberEvent.SUCCESS)).toBe(1);
        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(underTest.getCurrentBucket().get(RollingNumberEvent.SUCCESS)).toBe(2);
        expect(underTest.getCumulativeSum(RollingNumberEvent.SUCCESS)).toBe(2);

        support.fastForwardActualTime(RollingNumberRewired, 1500);
        underTest.increment(RollingNumberEvent.SUCCESS);
        underTest.increment(RollingNumberEvent.SUCCESS);
        underTest.increment(RollingNumberEvent.SUCCESS);

        expect(underTest.getCurrentBucket().get(RollingNumberEvent.SUCCESS)).toBe(3);
        expect(underTest.getCumulativeSum(RollingNumberEvent.SUCCESS)).toBe(5);
    });

    it("should accumulate events when reset happens", function () {
        const RollingNumberRewired = rewire("../../lib/metrics/RollingNumber");
        const underTest = new RollingNumberRewired({timeInMillisecond: 1000, numberOfBuckets: 2});
        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(underTest.getCumulativeSum(RollingNumberEvent.SUCCESS)).toBe(1);
        underTest.rollWindow(Date.now());
        expect(underTest.getCumulativeSum(RollingNumberEvent.SUCCESS)).toBe(1);
        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(underTest.buckets.length).toBe(2);

        support.fastForwardActualTime(RollingNumberRewired, 1001);

        underTest.increment(RollingNumberEvent.SUCCESS);
        expect(underTest.buckets.length).toBe(1);
        expect(underTest.getCumulativeSum(RollingNumberEvent.SUCCESS)).toBe(3);
    });

});