An Overview of JavaScript Testing in 2022

(Updated on: 21.11.2021)

This guide is intended to catch you up with the most important reasoning, terms, tools, and approaches to JavaScript testing for the year 2022.

It combines information from the best articles recently released (they are referenced at the bottom) and adds from my own experience.

It’s a little long but whoever reads and understands this guide, can safely assume they know the overall current state of JavaScript testing in the web development community.

Just a couple of years ago website testing had little documentation, was slow, hard to implement, not deterministic, and, generally, not pleasant to work on.

Nowadays, the website testing field has stabilized. Several testing tools receive very positive feedback from their users, well-known testing best practices has emerged, and testing became a more integral part of the job of web developers.

Today’s cutting edge website testing tools are fast, informative, and easy to work with. These tools would make your testing and developing experience much more enjoyable.

Looking forward, I forecast that AI would become more impactful in the field of automated tests. Some such tools already exist, and actively improving the workflow and experience of thousands of developers.

  • If you see anything I missed, got wrong, or is outdated, leave a comment and I’ll address it right away.
  • Notice the links at the bottom of the page. Reading them will allow you to deepen your knowledge in specific aspects of testing.

Enjoy :)

Test Types

You can read about different types of tests in more depth here and here and here.

In general, the central test types for websites are:

  • Unit Tests- Testing of individual units like functions or classes by supplying input and making sure the output is as expected:
  • Integration Tests- Testing processes across several units to achieve their goals, including their side effects:
  • End-to-end Tests (also known as “E2E Tests” or “Functional Tests”)- Testing user scenarios on the browser itself by controlling controlling the browser programmatically.
    These tests usually ignore the internals of applications and look at them like on a black box.

Running Tests

If I write a test, where would it run?

  • Tests can run in the browser by creating an HTML page with the test libraries and test files included as JS scripts.
  • Tests can run in a headless browser which is a way to launch browsers in a special mode where they run without actually rendering the UI on the screen. This way you can run them much faster in terms of performance and even entirely from the command line.
  • Tests can also be executed in Node.js by simply importing the test files that would import the files that are being test, that usually run on the browser.
    To simulate a browser-like environment, “window.location“ and such, jsdom is commonly used. Jsdom simulates whatever you get when you run your JS inside the browser like window, document, body, location, cookies, selectors but it doesn’t render anything.

Out of these three methods, I suggest using the third method (Node.js + jsdom) wherever possible. This method is much faster than the other two. However, the first and second methods may be more reliable because running bowser related code in the browser might be more reliable.

Test Tools Types

Test tools can be divided into the following functionalities. Some provide us with only one functionality, and some provide us with a combination.

It is very common to use a combination of several tools to cover all the needed test functionalities.

I will discuss each of them in-depth below, but first, let’s introduce them quickly.

  1. Test launchers are used to launch your tests in the browser or in Node.js with user config. (Karma, Jasmine, Jest, TestCafe, Cypress, webdriverio)
  2. Testing structure providers help you to arrange your tests in a readable and scalable way. (Mocha, Jasmine, Jest, Cucumber, TestCafe, Cypress)
  3. Assertion functions are used to check if a test returns what you expect it to return and otherwise, to throw a clear exception. (Chai, Jasmine, Jest, Unexpected, TestCafe, Cypress)
  4. Generate and display test progress and summary. (Mocha, Jasmine, Jest, Karma, TestCafe, Cypress)
  5. Mocks, spies, and stubs to simulate tests scenarios, isolate the tested part of the software from other parts, and attach to processes to test certain aspects of a scenario. (Sinon, Jasmine, enzyme, Jest, testdouble)
  6. Generate and compare snapshots to make sure changes to data structures from previous test runs are intended by the user’s code changes. (Jest, Ava)
  7. Generate code coverage reports of how much of your code is covered by tests. (Istanbul, Jest, Blanket)
  8. Browser Controllers simulate user actions for E2E Tests. (Nightwatch, Nightmare, Phantom, Puppeteer, TestCafe, Cypress)
  9. Visual Regression Tools are used to compare your site’s appearance to its previous versions visually by using image comparison techniques.
    (Applitools, Percy, Wraith, WebdriverCSS)

Let’s explain some of the terms mentioned above:

Test launchers

Launch a list of tests based on a configuration you provide (what browsers to run in, what babel plugins to use, how to format the output, etc).

Testing Structure

Refers to the organization of your tests. Nowadays, tests are usually organized in a BDD structure that supports behavior-driven development (BDD). It often looks like this:

Assertion Functions

Are used to make sure that tested variables contain the expected value. They usually look like one of these:

They are also really good in reporting issues when an unexpected value is returned. Instead of just failing, you get information about the structure of objects and exactly what is the difference between the expected object and the one the test actually outputs:

A failed test where 2 was expected, but got 1
A failed test where 2 was expected, but got 1
Jest report of a failed test

Spies

Attached to functions to provide extra information about them. For example, how many times a function was called, in which cases, by whom, what arguments were passed to it in each call?

Spies are used in integration tests to make sure that the side effects of a process or flow are expected. For example, how many times was a calculation function like execute called in the following case?

Stubbing / Dubbing / Function Mocking

Replaces selected methods of existing modules with user-supplied functions in order to ensure expected behavior during the test.

In many libraries, for example in jest, it can easily be done on functions you spy on.

For example here, we spy on isValid during the test, and unsubscribe after each test to make sure we don’t pollute the user object.

Mocks or Fakes

Used to fake certain modules or behaviors to test different parts of a processes.

Sinon can, for example, fake a server to ensure offline, fast and expected responses when testing a certain flow.

Snapshot Testing

Allows you to compare a data structure to what it was in older releases.

The following example, from the official Jest documentation, shows a snapshot test of a certain Link component.

It doesn’t actually renders and takes a picture of the component, but it saves its internal data in a separate file like this:

When the test runs, and the new snapshot differs from the last one, the developer is prompted to confirm that the change is intended.

Browser Controllers

There are several ways to control browsers to simulate user behavior, like clicking the mouse, drag and dropping, typing, and navigating.

  • A relatively new way of controlling browsers quickly became popular in the latest years. Browser maintainers added features to browsers that made them controllable using native APIs. For example puppeteer.
    Sometimes a framework might be used to expose the browser’s API in a different way.

Your code on Node.js <> (Maybe a framework) <> Browser's API

  • An older way that was used for many years was to install drivers on browsers that control the browser using different methods. This is how selenium works:

Your code on Node.js <> WebDriver <> FF/Chrome/Safari Driver <> Browser

  • Another way would be to inject scripts of a JS code that has access to the whole application environment: DOM, network, cookies etc… to raise events that simulate user behavior. Cypress.io uses this approach. For example, here is how you simulate a click:

document.getElementByID('someButton').dispatchEvent(clickEvent)

Putting it All Together

To start testing, you need to choose a testing structure that suits you, choose the style of assertion functions you like, and decide how do you want to run the tests.

I will discuss the tools you can choose from later in the article.

Some frameworks like Jest, Jasmine, TestCafe, and Cypress provide all of these out of the box. Some of them provide only some of the functionality and a combination of libraries can be used. A famous combinations of tools would be: mocha + chai + sinon.

I also suggest creating two different processes. One for running unit and integration tests and another one for E2E Tests. This is because functional tests usually take much longer to run, especially when running the test suite on several different browsers.

Unit and integration tests can run on the fly, as you code, using “watch mode” because they finish running in seconds. On the other hand E2E tests are usually launched before merges and releases. In some companies it takes hours to finish running all the E2E tests.

Unit Tests

Should cover all the small pure units of an application- utils, services and helpers. Provide all these units with simple and edge case inputs and make sure outputs are expected using assertion functions.
Also make sure to use a code coverage reporting tool to know which units are covered.

Integration Tests

Old school tests were focused on unit testing and resulted in applications where many small parts were working but the processes as a whole kept on failing.
Integration tests, on the other hand, detect cases where a unit is refactored and passes its tests but a process that depends on it fails.

The best demonstration of why testing more than each part of a system separately is important can be seen in this great GIF.

I created this GIF based on a slide in this great lecture by
Viv Richards that I recommend to watch.

It’s also important to remember that in the real world, for the reasons of imperfect design and the widespread use of black boxes, not all units are pure and not all units are testable- some units can be tested only as part of a bigger process.

Integration tests should cover important cross-module processes. Sometimes they extend to processes across several classes and sometimes to processes across different systems like Front-End-To-Back-End interactions.

Comparing to unit tests, you would probably benefit from using spies to ensure expected side effects instead of just asserting the output and stubs to mock and modify the parts of the process that are not in the specific test.

Component snapshot tests fall into this category as well. They provide us with a way to test how processes affect selected component structures and data structure without actually rendering them into a browser or a browser-like environment.

E2E Tests

Sometimes the quick and effective unit and integration tests are not enough.

E2E Tests (Functional Tests) control browsers and simulate user behavior in the browser (clicking, typing, scrolling etc…) and make sure these scenarios actually work from the point of view of an end user.

Also it is worth noting that many services provide you with devices and browsers to run these tests on. Here are even more services like these.

Visual regression testing tools can also be set up to verify that the different screens of your applications are ok visually by a smart comparison of screenshots. These screenshots are usually taken as part of your Functional Tests or by executing a separate session of browser automation.

Applitools smart visual regression tools

List of General Prominent Testing Tools

There are dozens of great tools out there. I couldn’t include all of them here but I tried to include the most important to know, best maintained , and the most adopted tools in the following list:

jsdom

jsdom is a JavaScript implementation of the WHATWG DOM and HTML standards. In other words, jsdom simulates a browser’s environment without running anything but plain JS.

As mentioned before, in this simulated browser environment, tests would run really fast. The drawback of jsdom is that not everything can be simulated outside a real browser (you can’t take a screenshot for example) so using it will limit your test’s reach.

It’s worth mentioning that the JS community rapidly improves jsdom and the current version is very close to support whatever exists on a real browser.

Storybook

While not, strictly speaking, a testing tool, Storybook lets you write components in special “stories” which enable developing and interacting with components in isolation.

Not only it encourages you to write your components in a more “testable” fashion, you can actually test the components in storybook, using Chromatic that I would discuss below.

Testing Library

Simple and complete testing utilities that encourages good testing practices. It is developed by Kent C. Dodds who is a testing guru. I suggest having a look at his work to learn more about best practices in testing websites.

The library provides special tools for different frameworks like React, Preact, React Native, Marko, Angular, Vue, and Svelte. The most famous of them is React Testing Library which is very widely adopted.

It also helps with E2E testing tools like Cypress, Puppeteer, Testcafe, and Nightwatch that would all be discussed next.

It helps with convenient selectors, firing events, configuration, dealing with asynchronous code, and many more.

Electron

The Electron framework lets you write cross-platform desktop applications using JavaScript, HTML and CSS. It also has a headless mode.

It has a huge community and many important applications are built on top of it, so it is supposed to stay up to date:
Atom, Slack, Skype, GitHub Desktop and many more.

Testing tools like Cypress.io use Electron to launch tests with maximum control of the browser.

Istanbul

Istanbul will tell you how much of your code is covered with unit tests. It will report on statement, line, function and branch coverage in percentages so you will understand better what is left to cover.

Karma

Karma hosts a test server with a special web page to run your tests in the page’s environment. This page can be run across many browsers and browser-like environments including jsdom.

Chai

Chai is the most popular assertion library. It has many plugins and extensions.

Unexpected

Unexpected is an assertion library with a slightly different syntax from Chai. It is also extensible so assertions can be more advanced with libraries that are based on it like unexpected-react that you can read about more in depth here.

Sinon.JS

Sinon has very powerful standalone test spies, stubs and mocks for JavaScript that works with any unit testing framework.

testdouble.js

testdouble is a less popular library that does what Sinon does, and claims to do it better. It has a few differences in design, philosophy, and features that could make it useful in some cases. I suggest learning it for the sake of understanding how these libraries work in principle.

You can read about it here, here and here.

Wallaby

Wallaby is another tool worth mentioning. It is not free, but many users recommend buying it. It runs on your IDE (it supports all major ones) and runs tests that are relevant to your code changes and indicates if anything fails in real time alongside your code.

Cucumber

Cucumber help with writing tests in BDD by dividing them between the acceptance criteria files using the Gherkin syntax and the tests that correspond to them.

Tests can be written in a variety of languages that are supported by the framework, including JS, which I focus on:

Many teams will find this syntax more convenient than TDD.

Choose Your Unit and Integration Tests Framework

The first choice you should probably make is which framework you want to use.

Here is a list of the most prominent tools with some of their characteristics:

Jest

Jest is the testing framework created and maintained by Facebook. It spiked in popularity and became the most popular testing library in 2017 and stayed in the first place since then.

It was initially based on Jasmine which I will discuss later. Over time, Facebook replaced most of its functionality and added a lot of features on top of it.

  • Performance- First of all Jest is considered to be faster for big projects with many test files by implementing a clever parallel testing mechanism.
  • UI- Clear and convenient.
  • Ready-To-Go- Comes with assertions, spies, and mocks that are equivalent to libraries that do the same like Sinon. Libraries still can easily be used in case you need some unique features.
  • Globals- Like in Jasmine, it creates test globals by default so there is no need to require them. This can be considered bad since it makes your tests less flexible and less controllable, but in most cases it just makes your life easier:
  • Snapshot testing- jest-snapshot is developed and maintained by Facebook, although it can be used in almost any other framework as part of the framework’s integration of the tool or by using the right plugins.
  • Great modules mocking- Jest provides you with an easy way to mock heavy modules to improve testing speed. For example a service can be mocked to resolve a promise instead of making a network request.
  • Code coverage- Includes a powerful and fast built-in code coverage tool that is based on Istanbul.
  • Reliability- Since it has a huge community, and used in many very complex projects, is is considered very reliable.
  • Support- It is currently supported by all the major IDEs and tools.
  • Development- jest only updates the files updated, so tests are running very fast in watch mode.

jasmine

Jasmine is the testing framework that Jest is based on. Why would you prefer Jasmine over Jest? It has been around for longer and it has a huge amount of articles, tools, and questions answered in various forums that were all created by the community over many years.

Also, the Angular team is using Jasmine, although Jest is perfectly suitable to run Angular tests as well, and many people do it.

  • Ready-To-Go- Comes with everything you need to start testing.
  • Globals- Comes with all the important testing features in the global scope.
  • Community- It has been on the market since 2009 and gathered a vast amount of articles, suggestions and tools that are based on it.
  • Angular- Has widespread Angular support for all its versions and it is recommended in the official Angular documentation.

mocha

Mocha was the most used testing library until 2019 (moving to be at second place after Jest). Unlike Jasmine or Jest, it is only a test runner so it has to be used with third party assertions, mocking, and spying tools (usually Sinon and Chai).

This means Mocha is a little harder to set up and divided into more libraries but it is more flexible and open to extensions.

For example, if you want special assertion logic, you can fork Chai and replace only Chai with your own assertion library. This can also be done in Jasmine but in Mocha this change will be more clear, expected, and obvious.

  • Community- Has many plugins and extension to test unique scenarios.
  • Extensibility- Very extensible, to the point where plugins, extensions and libraries are designed only to run on top of it.
  • Globals- Creates test structure globals by default, but obviously not assertions, spies and mocks like Jasmine. some people are surprised by this seemingly inconsistency of globals.

AVA

Ava is a minimalistic testing library that runs tests in parallel.

  • Ready-To-Go- Comes with everything you need to start testing (besides spying and dubbing that you can easily add). Uses the following syntax for test structure and assertions, and runs in Node.js:
  • Globals- As you can see above, it does not create any test globals, so you have more control over your tests.
  • Simplicity- Simple structure and assertions without a complex API while supporting many advanced features.
  • Development- Ava only updates the files updated so tests will run fast in watch mode.
  • Speed- Runs tests in parallel as separate Node.js processes.
  • Snapshot testing is supported as part of the framework.

tape

Tape is more low-level than the other test runners we saw. It’s just a JS file you run using node with a very short and “to-the-point” API.

  • Simplicity- Minimalistic structure and assertions without a complex API. Even more than Ava.
  • Globals- Does not create any test globals so you have more control over your tests.
  • No Shared State between tests- Tape discourages the use of functions like “beforeEach” to ensure test modularity and maximum user control over the testsing cycle.
  • No CLI is needed- Tape will simply run anywhere JS can run.

E2E Testing Tools

First of all, as mentioned above, here and here you can find great articles about service providers that will host the machines to run your tests on different devices and browsers.

The tools for the purpose of functional testing differ from each other in their implementation, philosophy, and API. Therefore it is strongly suggested to invest time in understanding the different solutions and testing them on your product.

selenium

Selenium and Selenium based tools have dominated the market of E2E Tests for years. It is not written specifically for testing and can control a browser for many purposes by using a driver that controls browsers using add-ins and browser extensions.

Node.js <=> WebDriver <=> FF/Chrome/IE/Safari drivers <=> browser

Selenium WebDriver can be accessed in many different ways and using a variety of programming languages, and with some tools even without any real programming.

The WebDriver can be imported into your testing framework and tests can be written as part of it:

The WebDriver itself might be sufficient for you and indeed some people suggest using it as is, but various libraries were created to extend it either by forking and altering it or by wrapping it.

Wrapping the WebDriver might result in a more clear API but might also add redundant code and could make debugging harder, whereas forking it might diverge it from the very active ongoing development of the WebDriver.

Still, some people prefer to not use it directly. Let’s look at some of the libraries for selenium:

Puppeteer

Puppeteer is a Node.js library, developed by Google. It provides a convenient Node.js API to control Chrome or Headless Chrome through an API the browser exposes: the DevTools Protocol.

Headless Chrome is just a regular Chrome v59+ that is launched with the
--headless flag. When Chrome is run in headless mode, it exposes an API to control it, and as said before, Puppeteer is the JavaScript tool that Google provides to control it.

Here it is worth mentioning that Firefox has also released their headless mode at the end of 2017.

Notice that different testing tools can also use Headless Chrome and Firefox. For example TestCafe, Karma, and Cypress.

  • Puppeteer is maintained by Google and has a big community that uses and develops tools and wrappers around it.
  • Since it is native and uses the latest Chrome engine, it is very fast.
  • One major drawback of Headless Chrome (thus of Puppeteer as well) is that it doesn’t support extensions like Flash and probably won’t in the near future.
  • Notice that this tool doesn’t come with a build-in testing system. Tools like mocha and chai can be used to create the necessary testing environment and structure around this library.

Playwright

Playwright is like Puppeteer extended to more browsers. It is developed by Microsoft by the team that originally developed Puppeteer.

The library automates Chromium, Firefox, and WebKit (Safari) by using the DevTools Protocol for Chromium, and similar technologies for other browsers.

It’s worth mentioning that since the library is pretty fresh (It was released in January 2020), breaking changes may be made in the near future and some things might not work or be documented as expected at the moment.

  • Cross Platform
  • Supports multiple tabs
  • Pretty new

Protractor

Update: The Angular team plans to **DEPRECATE** Protractor at the end of 2022.

Protractor is a library that wraps Selenium and provides us with improved syntax and special built-in hooks for Angular.

  • Angular- Has special hooks, although it can successfully be used with other JS frameworks too. Angular official documentation suggests using this tool (UPDATE: No longer. see the message above).

WebdriverIO

WebdriverIO uses a convenient syntax that controls the browser through its own implementation of WebDriver, distinct from selenium, or through DevTools Protocol using Puppeteer for Chromium.

It is an open source JS project that is used in JS environments (while selenium can be used with many programming languages).

  • Syntax- very easy and readable.
  • Flexible- A very simple, flexible, and extensible library.
  • Community- It has good support and enthusiastic developer community.
  • Applitools support, which is a visual regression library we will discuss later.

Nightwatch

Nightwatch has its own implementation of the selenium WebDriver. And provides its own testing framework with a test server, assertions, and tools.

  • Framework- Can be used with other frameworks too, but can be especially useful in case you want to run E2E tests, not as part of another framework.
  • Syntax- looks the easiest and the most readable.
  • Support- No typescript support and in general, this library seems to be slightly less supported than the others.

Appium

Apium provides an API similar to Selenium for testing websites on a mobile device using the following tools:

So if you use Selenium or Selenium-based tools, you can also use Apium to test on mobile devices.

TestCafe

TestCafe is a great alternative to Selenium-Based tools. It was rewritten and open-sourced at the end of 2016.

TestCafe had also a paid version that offered non-programming testing tools. It has been deprecated and got replaced by the new TestCafe Studio.

TestCafe injects itself into the website as JavaScript scripts instead of controlling the browsers themselves like Selenium does. This allows it to run on any browser, including on mobile devices, and have full control over the JavaScript execution loop.

Cypress

Cypress is a direct competitor of TestCafe. They are doing relatively the same, which is injecting tests into a website, but they try to do it in a more modern, flexible and convenient way.

The difference between them is that Cypress.io runs itself in the browser and controls your tests from there where TestCafe runs in Node.js and controls the tests through a serialized communication with its injected script in the browser.

Parallel testing was introduced in version 3.10.

  • Documentation- Solid and clear.
  • Native access to all your application’s variables without serialization (TestCafe on the other hand turns objects to JSON, sends them to Node.js as text and then parses them back to objects).
  • Very convenient running and debugging tools- Easy debugging and logging of the test process.
  • Cross-browser Support- since version 4.0.
  • Some use-cases are missing but in constant development such as lack of HTML5 drag-n-drop.
  • Using Mocha as the test structure provider makes its use pretty standard and allow your E2E tests to be built in the same structure as the rest of your tests.

CodeceptJS

Like CucumberJS which was discussed above, Codecept provides another abstraction over different libraries’ API’s to make your interactions with tests use a slightly different philosophy that focuses on user behavior.

Here is how it looks:

And here is the list of libraries that can be executed using this code. All discussed above.

WebDriverIO, Protractor, Nightmare, Appium, Puppeteer, and even the new Playwrigh.

If you believe this syntax is better for your needs, give it a shot.

PhantomJS

NOTICE: Its main maintainer, Vitaliy Slobodin, no longer works on it, and its development was suspended and its repository archived.

Phantom implements the chromium engine to create a controllable Chrome-like headless browser. It was a great tool to run in headless mode until Google announcement of “Puppeteer”.

Nightmare

Nightmare is an E2E Testing library that uses Electron which uses Chromium to control the browser.

Doesn’t seem to be maintained. Probably because of the introduction of “Puppeteer” as well which provides you with the same features out of the box.

Visual Regression Testing

The visual regression testing tools are consists roughly of the following:

  • Techniques and integrations to automate the browser or to run as part of E2E Testing tools discussed above, including in the CLI for CI.
  • Take smart screenshots as images and as DOM snapshots.
  • Images and DOM comparison techniques to spot differences sometimes even using advanced AI.
  • UI for humans to approve, reject and improve the comparison mechanism to only show what’s relevant for the user.

There are a lot of tools of this type in the market, but it feels like this field still has a long way to do.

Also, I noticed that paid tools in the visual regression testing category are much better than the free ones.

Applitools

  • Easy to set up.
  • Uses AI to make the comparison technique and human input regarding differences and negation of false positives very powerful.
  • It can be integrated conveniently with many of the tools discussed above.
  • Has a free and paid flexible plans, including special pricing for startup companies and non-profits.

Percy

  • Easy to set up.
  • Uses smart comparison techniques.
  • Convenient human input regarding differences.
  • It can be integrated conveniently with many of the tools discussed above.
  • It has great integrations with great tools.
  • Have free and paid flexible plans.

Happo

Happo is a paid visual regression testing tool. It hooks into the CI to compare the visual appearance of UI components before and after a change.

Screenshots can be taken in different browsers and across different screen sizes to ensure consistent cross-browser and responsive styling of your application.

Paid with a free plan for open source projects.

LooksSame

Yandex created this library alongside the now deprecated Gemini, which was a great simple-to-use visual regression testing tool.

Yandex now migrated to hermione that runs tests using WebdriverIO and Mocha.js and uses LooksSame for visual regressions. It is more simple and limited than the paid tools mentioned above, but for simple websites, it can be enough.

LooksSame can also be used on it’s own as long as you generate screenshots in any way you like.

BackstopJS

An open source visual regression utility that runs on Chrome Headless with Puppeteer and CI support.

AyeSpy

An open-source utility by the Times Tooling team at News UK.

Uses selenium docker to create visual regression tests on Chrome / Firefox.

reg-suit

An open-source library that compares images, generates reports and saves them on the cloud. Very convenient if you want to add visual regression tests to an existing E2E Test. Simply add steps of taking screenshots to your existing test flow and use it to compare these screenshots.

Differencify

Another open-source Chrome Headless using Puppeteer testing tool with nice integrations with Jest snapshots. Can run in docker and generates convenient reports.

No Coding E2E Testing Tools

testim

Opens your application in a separate window and uses a browser extension to record your manual interactions with the application as test scenarios.

Uses machine learning to help you record and validate test scenarios. Cross Browser and has some nice integrations with many CI and Collaboration tools.

Have free and paid flexible plans.

Chromatic

https://www.chromaticqa.com/

Chromatic is a visual testing tool for Storybook made by Storybook maintainers.

Diff Detector renders the UI of each story and takes a visual snapshot. If anything changes, you are prompted to accept the visual changes locally and as part of the project’s pipelines.

Screener

Lets you record your tests using a chrome extension, has in-depth visual regression reporting. Has some nice integrations like with storybook different CI tools and BrowserStack and Sauce Labs.

Not free.

Other tools of this type (you are free to suggest more in the comments):

Conclusion

We reviewed the most trending testing strategies and tools in the web development community and hopefully made it easier for you to test your sites.

In the end, the best decisions regarding application architecture today are made by understanding general patterns that are trending in the very active community of developers, and combining them with your own experience and the characteristics of your application.

Oh, and writing, and rewriting, and rewriting, and rewriting, and testing different solutions :)

Happy testings :)

Thanks :)

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