Examining the disparity between two dates through mocha/chai testing

Question

Examining the disparity between two dates through mocha/chai testing

I am currently utilizing "chai": "^4.2.0" and "mocha": "^6.1.4",.

Upon using assert.equal() to compare two dates, I encounter a discrepancy where the comparison returns false despite the dates appearing the same. Here is an example of the situation:

https://i.sstatic.net/dSnQz.png

Below is the test scenario in question:

  it('check if dates are correctly added', async () => {
let dataArr = [{'rating_date':'6/6/2019','impact_on_price':'Low'}]   
let priceServ = new PriceService()

// Clear all existing records
priceServ.clearPriceTable()

// Add 1 new record
const res = await priceServ.createOrUpdatePrice(dataArr)

// Retrieve all records from the table with a specific action attribute
const tableValues = await priceServ.getPricesByField('rating_date')
assert.equal(tableValues[0].rating_date, new Date(dataArr[0].rating_date));

});

Any guidance or insights on what might be causing this issue would be greatly appreciated.

Thank you in advance for your responses!

javascript mocha.js chai

Answer 1

Answer №1

The comparison of Date objects using Chai's assert.deepEqual function is accurate.

const { assert } = require('chai')

const a = new Date(0)
const b = new Date(0)
const c = new Date(1)

assert.deepEqual(a, b) // This is valid
assert.deepEqual(b, c) // This will cause an error

It is important to remember that both arguments passed to deepEqual must be Date objects and not other data types like string or number.

Answer 2

The comparison of Date objects using Chai's assert.deepEqual function is accurate.

const { assert } = require('chai')

const a = new Date(0)
const b = new Date(0)
const c = new Date(1)

assert.deepEqual(a, b) // This is valid
assert.deepEqual(b, c) // This will cause an error

It is important to remember that both arguments passed to deepEqual must be Date objects and not other data types like string or number.

Answer 3

Answer №2

Switching things up, consider opting to bring in the expect function instead of using assert. This allows you to take advantage of Chai's deep equality check method .eql(), like so:

  expect.eql(tableValues[0].rating_date, new Date(dataArr[0].rating_date));

This method is my preference because failure messages display plain dates, making troubleshooting a failing test much simpler.

Answer 4

Switching things up, consider opting to bring in the expect function instead of using assert. This allows you to take advantage of Chai's deep equality check method .eql(), like so:

  expect.eql(tableValues[0].rating_date, new Date(dataArr[0].rating_date));

This method is my preference because failure messages display plain dates, making troubleshooting a failing test much simpler.

Answer 5

Answer №3

Just a reminder from my previous comment, assert.equal actually checks for strict equality. You might want to consider comparing the timestamps instead:

assert.equal(tableValues[0].rating_date.getTime(), new Date(dataArr[0].rating_date).getTime());

Keep in mind that if the dates don't match up, the error messages can get pretty messy. There are some useful libraries available to help with that.

Answer 6

Just a reminder from my previous comment, assert.equal actually checks for strict equality. You might want to consider comparing the timestamps instead:

assert.equal(tableValues[0].rating_date.getTime(), new Date(dataArr[0].rating_date).getTime());

Keep in mind that if the dates don't match up, the error messages can get pretty messy. There are some useful libraries available to help with that.

Answer 7

Answer №4

Discover the chai-datetime plugin here.

How to Require:

const chai = require("chai");
const assert = chai.assert;
chai.use(require("chai"));

How to Import:

import chai, { assert } from "chai";
import chaiDateTime from "chai-datetime";
chai.use(chaiDateTime);

// original
assert.equal(tableValues[0].rating_date, new Date(dataArr[0].rating_date));

// with plugin
// compares only the date portion
assert.equalDate(tableValues[0].rating_date, new Date(dataArr[0].rating_date));
// compares timestamps
assert.equalTime(tableValues[0].rating_date, new Date(dataArr[0].rating_date));

// Additionally!
let date1 = new Date();
let date2 = date1.toISOString();
let date3 = date1.valueOf();
let date4 = date1.getTime();

assert.equalTime(date1, date1);
assert.equalTime(date1, date2);
assert.equalTime(date1, date3);
assert.equalTime(date1, date4);
assert.equalTime(date2, date1);
assert.equalTime(date2, date2);
assert.equalTime(date2, date3);
assert.equalTime(date2, date4);
// and so forth.
// There are also other assertions introduced, like before-, closeTo-, afterOrEqual-, within-, etc.

let date5 = new Date();
assert.afterOrEqual(date5, date1);
assert.closeTo(date5, date2, 5) // delta = within 5 seconds

Note: When testing, I personally prefer comparing timestamps as it simplifies the process. I once encountered an issue while working on a Java API connected to a MSSQL server with a JS frontend. On my local setup, saving birthdates and training dates functioned properly. However, when my supervisor accessed the live development server, every date saved would be shifted back by one day. This was due to the discrepancy in time zones causing the dates to be interpreted differently. To resolve this, I adjusted all dates to noon to ensure the timezone variance was less than twelve hours.

Answer 8

Discover the chai-datetime plugin here.

How to Require:

const chai = require("chai");
const assert = chai.assert;
chai.use(require("chai"));

How to Import:

import chai, { assert } from "chai";
import chaiDateTime from "chai-datetime";
chai.use(chaiDateTime);

// original
assert.equal(tableValues[0].rating_date, new Date(dataArr[0].rating_date));

// with plugin
// compares only the date portion
assert.equalDate(tableValues[0].rating_date, new Date(dataArr[0].rating_date));
// compares timestamps
assert.equalTime(tableValues[0].rating_date, new Date(dataArr[0].rating_date));

// Additionally!
let date1 = new Date();
let date2 = date1.toISOString();
let date3 = date1.valueOf();
let date4 = date1.getTime();

assert.equalTime(date1, date1);
assert.equalTime(date1, date2);
assert.equalTime(date1, date3);
assert.equalTime(date1, date4);
assert.equalTime(date2, date1);
assert.equalTime(date2, date2);
assert.equalTime(date2, date3);
assert.equalTime(date2, date4);
// and so forth.
// There are also other assertions introduced, like before-, closeTo-, afterOrEqual-, within-, etc.

let date5 = new Date();
assert.afterOrEqual(date5, date1);
assert.closeTo(date5, date2, 5) // delta = within 5 seconds

Note: When testing, I personally prefer comparing timestamps as it simplifies the process. I once encountered an issue while working on a Java API connected to a MSSQL server with a JS frontend. On my local setup, saving birthdates and training dates functioned properly. However, when my supervisor accessed the live development server, every date saved would be shifted back by one day. This was due to the discrepancy in time zones causing the dates to be interpreted differently. To resolve this, I adjusted all dates to noon to ensure the timezone variance was less than twelve hours.

Examining the disparity between two dates through mocha/chai testing

Answer №1

Answer №2

Answer №3

Answer №4

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