Testing web components vs. UI elements

User interface testing is crucial for the overall quality of software and its user experience. . Web component testing can be used to ensure that user interfaces are functional. UI testing, on the other hand, is an approach that takes the user perspective even more into account and can significantly increase the quality of software projects. Tools such as Cypress and Playwright make it possible to test front-end applications in isolation and offer versatile options for integration into existing test processes.

Podcast Episode: Testing web components vs. UI elements

In this episode, I talk to Felix Wunderlich about testing web components compared to UI testing. Felix works at Volkswagen AG and shares his experience with UI testing as an approach that better reflects the user perspective and increases efficiency. We discuss the use of tools such as Cypress and Playwright to test frontend applications in isolation. Felix reports on the challenges and successes of implementing this approach and provides insights into future developments in the testing environment.

"The main point is actually that with every change, no matter how small, we can be sure that our UI as a whole still works as it should from the user's perspective." - Felix Wunderlich

Felix Wunderlich is a passionate software developer with a particular fondness for functional programming, testing and complex problems. He studied computer science with a focus on software engineering, IT security and human computation at LMU Munich. Since 2018, he has been working as a software engineer at the Software Development Center of Volkswagen AG in Wolfsburg.

Highlights of the Episode

• Testing web components vs. user interface (UI)
• Challenges and solutions when testing frontend applications
• Using tools like Cypress and Playwright for testing
• Improving code quality through comprehensive testing
• Open environment for experiments and new ideas in the team

UI testing and web component testing: How to test user interfaces effectively

Introduction

User interface testing plays a crucial role in the software development process. UI testing not only makes it possible to appraise the user interface of applications and ensure that it meets user expectations. UI testing also helps to improve the overall experience for end users and create overall high-quality software. Test automation can help to further improve efficiency in testing and get better results faster. at.

This article covers the following topics: :

• The importance of testing web components
• Challenges and opportunities in UI testing
• Benefits and best practices for effective UI testing
• Insights into tools such as Playwright and Cypress

Why should you test web components?

Web components are reusable building blocks that allow developers to create complex user interfaces efficiently. They play a central role in modern web design as they offer modularity and flexibility. By using web components, teams can create consistent UI elements that can be used in different projects.

However, testing web components comes with some challenges:

• Complexity: The interaction between different components can cause unpredictable problems. For example, there is a risk that components may behave differently depending on their context within the application.
• Browser compatibility: Web components must work in different browsers. The variety of different browsers requires extensive testing to ensure that all users have a consistent experience.

Various approaches are available to meet these challenges:

• Test automation tools: Using tools such as Playwright or Cypress allows developers to automate tests and review the user interface from the end user's perspective. These tools support multiple browsers and improve the efficiency of the test process.
• Mocking techniques: By simulating backend responses, developers can perform isolated testing for their components. This reduces dependencies and speeds up the test process.

By integrating these strategies, web component testing becomes not only more effective, but also more practical for development teams who value quality.

UI testers: Why they are an important test strategy

What are UI tests?

UI tests (user interface tests) appraise the user interface of an application from the perspective of the end user. They differ from traditional component testing, which often tests isolated parts of the application. UI tests simulate real user scenarios and evaluate the behavior of the entire application, while component testing focuses on individual, isolated functions.

Advantages of UI testers:

• Real user experience: UI testers make it possible to test the application as a user would. This allows usability to be analyzed and the overall experience for end users to be improved.
• Early problem detection: By simulating real interactions, problems with the user interface can be detected early. This reduces the likelihood of bugs being discovered at later stages of the development process.
• End-to-end testing integration: While end-to-end testing is often time-consuming and complex, UI testing provides a faster and effective way to ensure that all parts of the application work together seamlessly.
• Time savings: The ability to run multiple tests in parallel significantly improves efficiency in testing. This enables faster feedback cycles and shorter development times.

The implementation of UI testers not only increases software quality, but also optimizes the entire development process. The early detection and elimination of problems increases the stability of the application. This creates a solid foundation for future developments.

To take full advantage of UI and web component testing, test automation is an important measure. Test automation with Selenium in particular has proven to be extremely effective. It enables precise testing and can be easily integrated into existing projects. You can read more about the basics and techniques of test automation in the book Basiswissen Testautomatisierung.

Tools for effective UI testing: A look at Playwright and Cypress

Choosing the right test automation tools is crucial for the success of UI testing. Playwright and Cypress are two of the most popular tools on the market when it comes to user interface testing.

Playwright

• Developed by Microsoft and allows you to run tests in multiple browsers (Chrome, Firefox and WebKit).
• Provides a powerful API to simulate complex user interactions.
• Supports mobile application testing through emulated mobile device support.
• Enables interception and mocking of network calls, which simplifies the execution of isolated tests.

Cypress

• Focuses on end-to-end testing and offers a user-friendly interface.
• Real-time test run: Instantly visualizes how your application responds to testing, making debugging easier.
• Ideal for developers who need quick feedback on UI changes. However, Cypress has limitations in supporting multiple browsers.

Focusing on the user perspective

The user perspective plays a crucial role in testing software applications. By understanding the needs and expectations of users, testers can ensure that the software developed is not only functional but also user-friendly. The following aspects should always be considered when testing software:

1. Identification of vulnerabilities

By putting themselves in the user's shoes, testers can identify potential problems that may arise during normal use of the software.

2. Realistic test scenarios

Tests based on realistic user scenarios provide valuable insights into the actual use of the software. This not only tests the functionality, but also improves the user experience.

User feedback is an important factor for testing user interfaces. Developers can align the software with the experiences of real users. The integration of user feedback leads to :

• More software quality: Direct feedback from users provides the opportunity to make specific adjustments based on the needs of the end user. This reduces the risk of errors and ensures greater satisfaction.
• Iterative development process: Continuously collecting and analyzing user feedback encourages an iterative approach to software development. Software can thus be adapted to user needs more quickly and dynamically.

Focusing on the user perspective thus has a direct influence on quality assurance and makes a decisive contribution to the development of high-quality software solutions. Test automationcan significantly increase efficiency in quality assurance.

In addition, the transition to open source test automation can be a valuable strategy. This approach not only increases efficiency, but also significantly reduces manual intervention.

Practical experience: The implementation of UI testing at Volkswagen

In recent years, VW Software Development has migrated from end-to-end testing and component testing to UI testing. The decision to move away from traditional testing methods was driven by the need for greater efficiency and a better user perspective.

Challenges

VW faced various challenges in its existing testing setup:

• Complexity of existing tests: The original end-to-end testing was time-consuming and often unreliable. These challenges of E2E test automation are a known problem in many companies.
• Reusability of components: For many user flows, identical tests had to be written multiple times, leading to redundancy.
• Changes in the CSS selectors: Such changes required adjustments to multiple test cases and resulted in additional effort.

Solutions

To overcome these hurdles, the following approaches were pursued:

• Centralization of UI elements: CSS selectors were collected in one place to facilitate maintenance.
• Utilization of mocking techniques: Simulated backend responses allowed the UI to be tested in its entirety without relying on a full system.
• Agile values as a foundation: The open exchange within the team promoted innovative solutions and accelerated the acceptance of new methods.

These measures not only led to faster test times, but also to higher software stability and quality.

Best practices for UI testing

Some of the most important best practices for effective UI testing include:

• Centralization of testing resources: All UI elements, CSS selectors, and backend communications should be centrally managed. This facilitates adjustments when changes are made to the API or frontend.
• Use of mocking techniques: By creating fake responses to backend requests, the frontend can be tested in isolation. This increases the speed and stability of the tests.
• Parallelization of tests: To increase efficiency, tests should be executed in parallel. Tools such as Playwright offer this possibility and thus reduce the total time for test runs.
• Experiment with new approaches: Teams should be encouraged to try out new testing methods. The iterative approach promotes innovation in the test process.

Conclusion: The importance of UI testing for software quality

Summarizing the findings shows that UI testing plays a central role in the software development process. The advantages are manifold:

• Early error detection: Problems with the user interface are identified at an early stage.
• Realistic user scenarios: Tests simulate real user interactions and behavior.
• Increased code quality: Regular UI testing improves software stability and reliability.

The implementation of UI testing has the potential to significantly increase software quality. With tools such as Playwright and Cypress, developers can test efficiently and ensure that their applications meet user requirements. Ultimately, this not only leads to higher user satisfaction, but also to less costly rework in later development phases. In the coming years, companies are expected to focus more on user-centered testing methods to meet the requirements of modern web applications. The acceptance and integration of such strategies could lead to UI testing becoming a standard practice in software development.

Frequently asked Questions

What is UI testing and why is it important?

UI testing refers to the appraisal of the user interface of a software application to ensure that it is user-friendly and functional. This helps to identify problems at an early stage and simulate realistic user scenarios.

What are the challenges of testing web components?

Challenges in testing web components include their complexity, the variety of browsers supported and the need to account for different user interactions. These factors can complicate the test process.

What advantages do UI tests offer compared to conventional component testing?

UI testing offers the advantage of being able to simulate end-to-end scenarios, which means that it covers the entire user experience. Unlike component testing, UI testing focuses on the behavior of the application from the end user's perspective.

What are Playwright and Cypress and how do they differ?

Playwright and Cypress are two popular tools for UI testing. Playwright supports multiple browsers and allows testing of applications in different environments, while Cypress offers a user-friendly interface and is well suited for quick iterations during development.

How can the user perspective improve quality assurance in the test process?

Taking the user perspective into account in the test process enables teams to obtain feedback directly from users. This leads to a better adaptation of the software to the needs of the end users and contributes to improving the overall quality.

What best practices should companies follow in UI testing?

Companies should develop a clear test strategy, regularly update automated tests and integrate user feedback into the test process. In this way, the effectiveness of UI testing can be maximized.