What is asynchronous testing?

Code that runs asynchronously is prevalent in JavaScript. When testing asynchronous code, the testing framework needs to know when the code it's testing is finished before it can move on to the next test.

What is callback in MOQ?

A callback is a piece of code that is supplied as a parameter to a method and then run within that function. You can use callbacks to expand the functionality of these functions. You can provide a callback code when an expectation is satisfied while using Moq to construct test doubles.

Which is better: jest or mocha?

In Node.js, Mocha is commonly utilised. It focuses on a variety of test types, including unit, integration, end-to-end testing and offers more flexibility than jest.

What are spies stubs and mocks?

Stubs are mainly utilised in test suites that aren't too complicated. Mocks are most commonly employed in big test suites. When utilising fake objects, the default behaviour of methods is to do nothing (unless they are stubbed) (performs nothing.) When employing spy objects, the default behaviour of the methods is the genuine method behaviour (when not stubbed).

Table of contents

Introduction

Getting Started

2.1.

package.json

2.2.

Test Program

2.3.

Output

2.4.

Run the command given below

FAQs

Key Takeaways

Last Updated: Mar 27, 2024

Testing double callbacks

Author Aman Thakur

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Introduction

In javascript language, a double-callback is a callback that we anticipate to be called once but gets called twice or more times for whatever reason. To test those we basically uses the mocha known to be testing double callbacks.
This article will go through the sequence in which Mocha's components are executed. It's worth noting that all hooks, describe, and callbacks will be executed in the order you specify. That is, precisely as they appear in your test file.

Getting Started

Before getting started with writing our test for double callbacks go ahead with the necessary setup needed for the article mentioned below. Run the basic command such as yarn init or npm init. To initialise the project with package manager of your choice.

package.json

Note that if you don’t specify the test script as mentioned below then you have call it through the .node_modules folder by specifying the path of mocha.test.js

{
 "name": "aync-mocha-test",
 "version": "1.0.0",
 "main": "index.js",
 "author": "aman-thakur",
 "license": "MIT",
 "dependencies": {
   "axios": "^0.26.0"
 },
 "scripts": {
   "test": "mocha index.js"
 },
 "devDependencies": {
   "mocha": "^9.2.1"
 }
}

Test Program

// create file index.js 
const assert = require("assert");

it("double codingninjas",  (codingninjas) => {
 setImmediate(codingninjas);
 setImmediate(codingninjas);
});

You can also try this code with Online Javascript Compiler

Run Code

Output

Run the command given below

If you are using npm:

npm test

Or, if you are using yarn:

yarn test

FAQs

What is asynchronous testing?
Code that runs asynchronously is prevalent in JavaScript. When testing asynchronous code, the testing framework needs to know when the code it's testing is finished before it can move on to the next test.
What is callback in MOQ?
A callback is a piece of code that is supplied as a parameter to a method and then run within that function. You can use callbacks to expand the functionality of these functions. You can provide a callback code when an expectation is satisfied while using Moq to construct test doubles.
Which is better: jest or mocha?
In Node.js, Mocha is commonly utilised. It focuses on a variety of test types, including unit, integration, end-to-end testing and offers more flexibility than jest.
What are spies stubs and mocks?
Stubs are mainly utilised in test suites that aren't too complicated. Mocks are most commonly employed in big test suites. When utilising fake objects, the default behaviour of methods is to do nothing (unless they are stubbed) (performs nothing.) When employing spy objects, the default behaviour of the methods is the genuine method behaviour (when not stubbed).

Key Takeaways

If you get through here, you definitely get to learn something new in this article, such as how Mocha's components are executed. All hooks, descriptions, and callbacks will be run in the specified order. That is, they must look precisely as they do in your test file.

Hence never stop your quest for learning, you might be interested in articles such as Mocha Runcycle and Fundamentals of Software Testing go ahead and check them out. which will assist you in gaining a better knowledge of the topic.We wish you Good Luck! Keep coding and keep reading Ninja. Do put an upvote if you find this article useful.

Happy Learning!