Frontend Test – Explaining

Frontend Testing

Frontend Testing is a technique in which Graphical User Interface (GUI), functionality and usability of web applications or software tests. Testing as part of the system, which many developers think is the opposite since they deploy. He states it is a catastrophic point of view since testing supports the development and keeps the system robust and changing.

For Example:

If you enter your name into the application’s front end, numbers should not be accepted. An extra example would be checking the alignment of GUI elements.

In the Front End, the end users’ interactions with our application are commonly checked. We must ensure our users that when they connect, open a pop-up, add a comment or do any other interaction with our applications, they do not encounter any errors and experience unwanted.

Apart From this, Frontend Testing is Shown for:

  • CSS Regression Testing: Minor CSS variations that break the frontend layout
  • Variations to JS files that make the Frontend non-functional
  • Performance Checks

Frontend testing, if done correctly, will ensure that our users are happy and have a good performance experience using our applications. On the other hand, developers will save a lot of time when it comes to solving bugs or adding new features, and it will not break the previous behaviour of the code.

Why is Frontend Testing can be Disadvantageous? How to Design a Test System?

Testing requires time and also consistency with changes during development. Also, with the growth of devices and browsers, you have to stay up to date. There is a concept known as the Fragile Tests Problematic in software testing—this is defined as a system change that causes hundreds of tests to fail. Uncle Bob emphasizes the importance of a well-designed test system to gain our systems’ desired stability and regression benefits.

We will Describe Some Methodologies and Plans that can Help the Design of our Frontend Testing Systems:

In his article « On the Various and Fantastical Shapes of Testing, ” Martin Fowler recounts a testing expert asking about the unit testing definition. This expert’s response covered 24 different unit test definitions on the first pre-launch of his training course. Since there are many different meanings of the unit test, we will include what Fowler calls the “solitary test” in this article.

At the bottom of the famous testing pyramid, we find the unit tests that have less test coverage but are the fastest to execute. We see the addition tests with more coverage but are slower in the second level since they can connect with external parties. Finally, we have the E2E tests or acceptance tests that cover a large part of the application but are the slowest to execute.

Some Frontend Testing of Components Work

Unit tests verify that our components work correctly in isolation. They also cover edge cases for testing, making our codebase more reliable. Integration tests follow the tests or unit tests. Integration tests check the communication between two independently developed software units or modules. They analyze the behaviour of systems when they are connected and study the interaction between microservices. They also include the API connection, so they are slower than unit tests since the connection may delay or the service may be down. In the Frontend, the integration tests  use to verify that the data returned by the API has the object,

E2E tests simulate user behaviour and check all user interactions with our application. They specialize in versions of additional tests that run on real browsers. They are typically run before merges or releases, as it can take hours to finish the test run.

frontend test

Next, we also Mention Fronting Testing Techniques such as Accessibility and User Interface:

Accessibility tests check that the user interface is easily usable by all users and make our application usable by people with disabilities. Jest-axe is a great Jest testing library that allows us to test the accessibility of our applications. You can also refer to this article by my colleague Serhii to explain accessibility tests fully.

UI tests check if the user boundary of our request works appropriately. If a user enters input, clicks a checkbox, or deletes an item, it should work correctly and update the UI state.

Review of some Frontend Testing Libraries for Frontend

Jest library uses for unit and integration tests in Frontend. It is fast for large projects with many test files because of its intelligent parallel test implementation mechanism. Testing Library is a library where we can write unit and integration tests. Help with convenient selectors, firing events, configuration, asynchronous code, and more.

Cypress is a library that injects its tests into a website that runs itself in the browser. We can write unit, addition and end-to-end tests efficiently. It provides a faster experience for developers, and we can easily see errors in the browser.

Apple tools use for visual regression tests. Its advanced AI techniques detect the differences between images and the DOM. It is advantageous to check if the appearance of our website is the same as the previous one or if an error has occurred. It also contains different browsers and platforms if the user can correctly see any element, such as a website or mobile button.


Frontend testing should be part of our development to fix problems in our code before it goes into production. We must write unit tests that examine each functionality of our applications and development. Integration tests to check if all the workings and units work correctly together. On the other hand, we should write E2E exams that automate manual tests and focus on how users interact.

We must write tests to provide confidence and not just improve the measurement system. As Robert C. Martin says, we must avoid writing exams tightly coupled to the system because even the most trivial change can generate a lot of difficulties to break.