Most software systems are deployed without being completely tested. The result is faults discovered by end users. Testing is done under time and budget constraints hence testing may not be comprehensive: only some portions of the systems get fully and properly tested before going live. The goal of this article is to motivate developers with regards to the importance of testing in the presentation layer of a 3 Tier Architecture.

What is Testing?

Testing is a process through which we try to analyze, understand and measure the observed behavior of a system against the expected behaviors we require from the system.

What is Frontend Testing?

Frontend testing is a type of testing in which the Graphical User Interface (GUI), functionality and usability of web applications or a software are tested. The main goal of frontend testing is to ensure that the presentation layer of the system works as expected with successive updates.

Why Frontend Testing?

There is a dramatic shift in functionality from server to clients; Angular, React, Vue and other frontend frameworks bring many complexities in the client side so it is important that every user is well-protected from bugs in the presentation layer. Some key considerations that have arisen from recent [changes to?]:

• There are now more codes to write in the client side of applications than ever before.
• Websites and web applications are now expected to be more available on browsers.
• We deal more with third party services in applications.
• The internet is now for everybody, so we face a greater variety of audience in our applications.

Unit Testing

Unit testing finds differences between the object design model and its corresponding component. It tries to test the functionality of the system in an isolated manner.

End to End (E2E) Testing

E2E testing is a type of testing of an application’s workflow: the flow in which the users behave from beginning to end. This type of test validates the application for integration and data integrity.

How to Have a Frontend Testing Plan?

Not every software or application can be completely tested; we test them as we expect them to behave as needed in particular situations under a measured number of conditions.

The steps necessary for creating a well-prepared plan can be:

1. Find out the tools for managing the tests (almost always the most important step)
2. Specify the amount of budget for frontend testing
3. Have clear vision on the entire process timeline
4. Define the scope in which the application is tested

The scope can be the type of OS or browsers used by end-users, popular devices and machines, the diversity of users and their internet connection and speed.

Frontend Tools and Frameworks

As mentioned above, finding the best tool or framework may be more challenging than writing the tests. For instance, the wrong decision over the testing tool or framework can lead to wasted time and budget. Start by being very clear on the goal of testing in your application. There’s a large variety of tools and frameworks each of which can be good or bad in different situations; only a clear vision on your test requirements can lead to the right choice of the tools or framework.

Here I have provided a comparison between some popular frontend testing tools and frameworks. Each tries to cover and detect software failures, provide errors and lets you discover and correct them before you deploy your application to be ready for end users usage.

Popular Testing Tools and frameworks

• LambdaTest
• Jasmine
• Selenium
• Needle
• Cypress
• Jest
• WebdriverIO
• TestCafe
• Codeceptjs
• applitools

Testing Tools/Frameworks Pros and Cons

LambdaTest (selenium-based)

Pros

• geolocation testing
• select browsers, timezone, country
• scale up with parallel testing
• Integration with project management tools
• Automates browsers with paid version

Cons

• High amount of pricing
• When switched between the versions of the browser, the session expires

Selenium

Pros

• Support for various languages, python, java, ruby, pearl, PHP
• Open Source, free, Simple record and playback UI
• high customization abilities and the ease of use
• Browser Control
• Automates browsers

Cons

• Recognize Adobe Flash and MS SilverLight elements without additional help

Cypress (non-selenium-based)

Pros

• Interacts directly with the browser
• Automatic waiting for invisible elements
• Screenshots and videos

Cons

• No mobile testing support
• Support chrome and electron family browsers only
• No Browser Control
• Simulated Events

TestCafe (non-selenium-based)

Pros

• Interacts directly with the browser
• Open-source
• Easy to configure browsers
• Focus only on tests
• Good dashboard reports
• Mobile browser support
• cross browser testing

Cons

• No Browser Control
• Simulated Events
• Not very well built-in wait mechanism

CodeceptJs

Pros

• Full browser control
• Open source
• Flexible Driver

Cons

• Small community
• Not a framework by itself

Jasmine

Pros

• Can be used for TDD
• Open source
• Great community
• Jasmine is faster than selenium in angular application

Cons

• Unfriendly error logs

Applitools

Pros

• AI-powered visual regression

Cons

• Less review ranking than lambdaTest

As you notice all tools and frameworks have pros and cons: different situations and scenarios may need more thinking for your choices, the plan you sketch out should also guide your future vision on frontend testing. It will be up to you to do your own investigating but here I have shortlisted some of these tools you may find useful in your frontend testing.

Recommendations for Selenium-Based E2E Testing Tools and Frameworks

LambdaTest — Although lambdaTest has high amount of pricing and subscription it is a great tool with great abilities, it is a pixel to pixel testing tool not AI-Powered like Applitools

Selenium — Free, open source and great community it can be best choice if we care about subscription values

Recommendations For Non-Selenium-Based E2E Testing Tools and Frameworks

Cypress — If we don’t mention lack of mobile browser supports Cypress is a great tool the power of automatic waiting along screenshots and video capturing with fast running of tests make Cypress a one stop place for testing applications

TestCafe — Among JS-Based test frameworks TestCafe is a great tool it supports all major browsers for cross browser testing, runs fast and has a vast community.

Recommendations for Unit Testing Tools and Frameworks

Jest — One stop shop for unit testing is powered by facebook, high number of collaborators and stars on GitHub, easy to setup and run.

Testing should be a non-negotiable part of software development, plan for it from earlier stages of your work, invest time, effort and resources so the users of your application wouldn’t deal with unwanted disruption in their experience.