Belitsoft > Types of Front End Testing in Web Development

Types of Front End Testing in Web Development

A lack of testing can lead to frequent and significant issues in production. This is because without tests, code changes are not systematically validated, increasing the risk of introducing errors. In a company without a testing culture, issues often only become evident after deployment, leading to emergency fixes and increased pressure on senior developers.


Cross-Browser and Cross-Platform Testing

Strategies in Cross-Browser and Cross-Platform Testing

There are two common strategies: testing with developers or having a dedicated testing team.

Developers usually only test in their preferred browser and neglect other browsers, unless they are checking for client-specific or compatibility issues.

The Quality Assurance (QA) team prioritizes finding and fixing compatibility issues early on. This approach ensures a focus on identifying and resolving cross-browser issues before they become bigger problems. The QA professionals use their expertise to anticipate differences across browsers and use testing strategies to address these challenges.

Tools for Cross-Browser and Cross-Platform Testing

Specific tools are employed to guarantee complete coverage and uphold high quality standards. This process involves evaluating the performance and compatibility of a web application across different browsers, including popular options like Firefox and Chrome, as well as less commonly used platforms.

  • Real device testing: Acknowledging the limitations of desktop simulations, the QA team incorporates testing on actual mobile devices to capture a more accurate depiction of user experience. This is a fundamental practice for mobile application testing services, enhanced by detailed checklists and manual testing to achieve this.
  • Virtual machines and emulators: Tools like VirtualBox are used to simulate target environments for testing on older browser versions or different operating systems. Services like BrowserStack offer virtual access to a wide range of devices and browser configurations that may not be physically available, facilitating comprehensive cross-browser/device testing.
  • Developer tools: Browsers like Chrome and Firefox have advanced developer tools that allow for in-depth examination of applications. These tools are useful for identifying visual and functional issues, although they may not perfectly render actual device performance, leading to some inaccuracies. Quite often, when the CSS tested in Chrome's responsive mode appears correct, clients report issues, highlighting discrepancies between simulated and actual device displays. Mobile testing in dev tools has limitations like inaccurate size emulation and touch interaction discrepancies in browsers. We have covered mobile app testing best practices that can bridge the gap for optimal performance across devices and user scenarios in this article.
  • CSS Normalization: Using Normalize.css helps create a consistent baseline for styling across different browsers. It addresses minor CSS inconsistencies, such as varying margins, making it easier to distinguish genuine issues from stylistic discrepancies.
  • Automated testing tools: Ideally, cross-browser testing automation tools are integrated into the continuous integration/continuous deployment (CI/CD) pipeline. These tools are configured to trigger tests as part of the testing phase in CI/CD, often after code is merged into a main branch and deployed to a staging or development environment. This ensures that the application is tested in an environment that closely replicates the production setting. These tools can capture screenshots, identify broken elements or performance issues, and replicate user interactions (e.g., scrolling, swiping) to verify functionality and responsiveness across all devices before the final deployment.

We provide flawless functionality across all browsers and devices with our diverse QA testing services. Reach out to ensure a disruption-free user experience for your web app.

Test the applications on actual devices

To overcome the limitations of developer tools, QA professionals often test applications in actual devices or collaborate with colleagues for accurate cross-device compatibility. Testing on actual hardware provides a more precise visual representation, capturing differences in spacing and pixel resolution that simulated environments in dev tools may miss.

Testing on actual hardware gives a more accurate visual representation. It captures spacing and pixel resolution differences that may be missed in simulated environments in dev tools. Firefox's Developer Tools have a feature for QA teams. It lets them inspect and analyze web content on Android devices from their desktops. This helps understand how an application behaves in real devices. It highlights device-specific behaviors like touch interactions and CSS rendering. These behaviors are important for ensuring a smooth user experience.

This method is invaluable for spotting usability issues that might be ignored in desktop simulations. Testing on a physical device also allows QA specialists to assess how their application performs under various network conditions (e.g., Wi-Fi, 4G, 3G), providing insights into loading times, data consumption, and overall responsiveness. Firefox's desktop development tools offer a comprehensive set of debugging tools, such as the JavaScript console, DOM inspector, and network monitor, to use while interacting with the application on the device. This integration makes it easier to identify and resolve issues in real-time.

Testing on physical device, despite its usefulness, is often overlooked, possibly because of the convenience of desktop simulations or a lack of awareness about the feature. However, for those committed to delivering a refined, cross-platform web experience, it represents a powerful component of the QA toolkit, ensuring thorough optimization for the diverse range of devices used by end-users. The hands-on approach helps QA accurately identify user experience problems and interface discrepancies.

In the workplace, a 'device library' offers QA professionals access to various hardware like smartphones, tablets, and computers. It also helps in testing under different simulated network conditions. This allows the team to evaluate how an application performs at different data speeds and connectivity scenarios, such as Wi-Fi, 4G, or 3G networks. Testing in these diverse network environments ensures that the application provides a consistent user experience, regardless of the user's internet connection.

When QA teams encounter errors or unsupported features during testing, they consult documentation to understand and address the issues, refining their approach to ensure compatibility and performance across all targeted devices.

For a deeper insight into refining testing strategies and enhancing software quality, explore our guide on improving the quality of software testing.

Integration Testing & End-to-end Testing

Increased code reliability confidence is a key reason for adopting end-to-end testing. It allows for making significant changes to a feature without worrying about other areas being affected.

As testing progresses from unit to integration, and then to end-to-end tests within automated testing frameworks, the complexity of writing these tests increases. Automated test failures should indicate real product issues, not test flakiness.

To ensure the product's integrity and security, QA teams aim to create resilient and reliable automated tests.

In the transition from unit to integration and end-to-end tests, complexity rises. It's crucial for tests to identify genuine product issues, avoiding failures due to test instability.

Element selection

Element selection is a fundamental aspect of automated web testing, including end-to-end testing.

Automated tests simulate user interactions within a web application, like clicking buttons, filling out forms, and navigating through pages. To achieve this, modern testing frameworks, like test automation framework, are essential as they provide efficient and reliable strategies for selecting elements. For these simulations to be effective, the testing framework must accurately identify and engage with specific elements on the web page. Element selection facilitates these simulations by providing a mechanism to locate and target elements.

Modern web applications introduce additional complexities, with frequent updates to page content facilitated by AJAX, Single Page Applications (SPAs), and other technologies that enable dynamic content changes. Testing in such dynamic environments requires strategies capable of selecting and interacting with elements that may not be immediately visible upon the initial page load. These elements become accessible or change following certain user actions or over time.

The foundation of stable and maintainable tests lies in robust element selection strategies. Tests that are designed to consistently locate and interact with the correct elements are less likely to fail due to minor UI adjustments in the application. This enhances the durability of the testing suite.

The efficiency of element selection affects the speed of test execution. Optimized selectors can speed up test runs by quickly locating elements without scanning the entire Document Object Model (DOM). This is especially important in continuous integration (CI) and continuous deployment (CD) pipelines, with frequent testing.

Tools such as Cypress assist with this by enabling tests to wait for elements to be prepared for interaction. However, there are constraints like a maximum wait time (e.g., two seconds), which may not always align with the variability in how quickly web elements load or become interactive.

WebDriver provides a simple and reliable selection method, similar to jQuery, for such tasks.

When web applications are designed with testing in mind—especially through the consistent application of classes and IDs to key elements—the element selection process becomes considerably more manageable. In such cases, issues with element selection are rare, and mostly occur when unexpected changes to class names happen, which is more of a design and communication problem within the development team rather than the issue with the testing software itself.

Component Testing 

Write Сustom Сomponents to save time on testing third-party components 

QA teams might observe that when a project demands full control over its components, opting to develop these in-house could be beneficial. This ensures a deep understanding of each component's functionality and limitations, which may lead to higher quality and more secure code. 

It also helps avoid issues like vulnerabilities, unexpected behavior, or compatibility problems that can arise from using third-party components.  

By vetting each component thoroughly, the QA team can ensure adherence to project standards and create a more predictable development environment during software testing services.

When You Might Need to Test Third-Party Components

Despite the advantages of custom components, there are certain scenarios where the use of third-party solutions is necessary. These scenarios include:

  1. When a third-party component is integral to your application's core functionality, test it for expected behavior in specific use cases, even if the component itself is widely used and considered reliable. 
  2. If integrating a third-party component requires extensive customization or complex configuration, testing can help verify that the integration works as intended and doesn't introduce bugs or vulnerabilities into your application.
  3. In cases where the third-party component lacks a robust suite of tests or detailed documentation, conducting additional tests can provide more confidence in its reliability and performance.
  4. For applications where reliability is non-negotiable, like in financial, healthcare, safety-related systems, even minor malfunctions can have severe consequences. Testing all components, including third-party ones, can be a part of a risk mitigation strategy.

Snapshot Testing in React development 

Snapshot testing serves as a technique used in software testing to ensure the UI does not change unexpectedly. In React development projects—a popular JavaScript library for building user interfaces—snapshot testing involves saving the rendered output of a component and comparing it with a reference 'snapshot' in subsequent tests to maintain UI consistency. The test fails if the output changes, indicating a rendering change in the component. This method should catch unintended modifications in the component's output.

As the project evolves, frequent updates to the components lead to constant changes in the snapshots. Each code revision might necessitate an update to the snapshots, a task that becomes more challenging as the project scales, consuming significant time and resources.

Snapshot testing can be valuable in certain contexts. However, its effectiveness depends on the project's nature and implementation. For projects with frequent iterations and updates, maintaining snapshot tests may have more disadvantages than benefits. Tests may fail due to any change, resulting in large, unreadable diffs that are difficult to parse.

Improve the safety and performance of your front-end applications with our extensive QA and security testing services. Contact us now to protect your web app and deliver an uninterrupted user experience.

Accessibility Testing

Fundamentals and Broader Benefits of Web Accessibility

The product should have some level of accessibility instead of being completely inaccessible.

Incorporating alt text for images, semantic HTML for better structure, accessible links, and color contrast is vital for making digital content usable by people with disabilities, such as those who use screen readers or have visual impairments. 

The broader benefits of accessibility testing extend beyond aiding individuals with disabilities but also enhance overall usability, such as keyboard navigation and readability.

Challenges and Neglect in Implementing Web Accessibility

Implementing accessibility features often requires time, resources, and, sometimes, specialized skills. This can be difficult due to economic or resource constraints. Adding accessibility features takes extra design and development time, which can be challenging when working with tight deadlines. After a product is launched, the focus often shifts to avoid changes that could disrupt the product, making accessibility improvements less of a priority. Easy-to-implement accessibility elements may be included during initial development, but more complex features are often overlooked.

Companies may not allocate resources for accessibility features unless there is a clear customer demand or legal requirement. Media companies recognize the need for certain accessibility requirements and make efforts to ensure their apps are accessible, such as considering colorblind users in their branding and style choices. Government projects strictly enforce accessibility requirements and consistently implement them.

A lack of support and prioritization occurs when there is not a strong emphasis or commitment to ensuring products are accessible. This is a common situation in web development, where accessibility considerations are often secondary. Accessibility is not yet recognized as a critical aspect of development and is thus not actively encouraged or mandated by leadership.

Even when implemented, these features are often neglected over time. Accessible websites require active testing to accommodate all users, including those who rely on assistive technologies like screen readers.

Automating Web Accessibility Checks

Software tools can automatically check certain accessibility elements of a website or app.

Examples include:

  • Ensuring images include alternative text (alt text) for screen reader users.
  • Verifying proper labeling of interactive elements like buttons to assist users with visual or cognitive impairments in navigation and understanding.
  • Checking the association of input fields with their respective labels for clarity in forms, which helps users understand what information is required.

Development tools in browsers, particularly Firefox's developer tools, are increasingly valuable for conducting accessibility testing, revealing potential barriers.

Limitations of Accessibility Tools

Accessibility tools can sometimes be complex or tricky to implement without proper guidance or experience. For instance, VoiceOver, an accessibility tool on Mac, encounters technical issues that can prevent its effective use.

Tools like WAVE and WebAxe are helpful in identifying certain accessibility issues, such as missing alt tags or improper semantic structure, but they cannot address all aspects. 

For example:

  • They are not able fully to assess whether the website's semantic structure is correct, including proper heading hierarchy.
  • They cannot determine the quality of alt text, such as whether it is descriptive enough.
  • They have limitations in checking for certain navigational aids like skip navigation links, which are important for keyboard-only users.

Automated accessibility testing has a limitation in assessing color contrast with text overlapping image backgrounds. This is because the color contrast can vary based on the colors and gradients of the underlying image.

Web accessibility standards and the different levels of compliance

Adherence to web accessibility standards, such as the Web Content Accessibility Guidelines (WCAG), is not only a matter of legal compliance in many jurisdictions but also a best practice for inclusive design. These standards are categorized into different levels of compliance: A (minimum level), AA (mid-range), and AAA (highest level). Each level imposes more stringent requirements than the previous one.

Resources like the Accessibility Project (, the Mozilla Developer Network (MDN), and educational materials by experts such as Jen Simmons help developers, designers, and content creators understand and effectively implement accessibility standards.

Performance Testing

Varied Approaches to Performance Testing by QA Team

For performance testing, QA teams adopt diverse strategies. The aim is to identify potential bottlenecks and areas for improvement without relying solely on specific development tools or frameworks.

Challenges in Assessing Website Performance

Assessing website performance is challenging due to unpredictable factors like device capabilities, network conditions, and background processes.

This unpredictability makes performance testing unreliable, as test results can vary significantly. For example, using tools like Puppeteer can be affected by device performance, background processes, and network stability.

At Belitsoft, we address performance testing challenges by employing the Pareto Principle. This allows us to enhance efficiency while maintaining the quality of our work. Learn how Belitsoft applies the Pareto principle in custom software testing in this article.

Common Tools for Performance Testing in Pre-Production

During the pre-production phase, QA teams use a suite of tools like GTMetrix, Lighthouse, and Google Speed Insights to thoroughly assess website speed and responsiveness. For example, Lighthouse provides direct feedback on areas requiring optimization for metrics such as SEO and load times. It highlights issues such as oversized fonts that slow down the site, ensuring QA teams address specific performance problems.  

The Importance of Monitoring API Latencies for User Experience

However, API latencies—delays in response time when the front end makes requests to backend services—are critical for shaping user experience but not always captured by traditional page speed metrics. Teams can establish early warning systems for detecting performance degradation or anomalies by integrating alarms and indicators into their comprehensive API testing strategy, enabling timely interventions to mitigate impacts on the user experience. 

Tools for Monitoring Bundle Size Changes During Code Reviews

Integrating a performance monitoring tool that alerts the QA team during code reviews, like GitHub pull requests, about significant bundle size changes is essential. This tool automatically analyzes pull requests for increases in the total bundle size—comprising JavaScript, CSS, images, and fonts—that exceed a predefined threshold. This guarantees that the team is promptly alerted to potential performance implications.

Unit Testing

End-to-End vs. Unit Tests

End-to-end testing simulates real user scenarios, covering the entire application flow. They are effective in identifying major bugs that affect the user's experience across different components of the application. In contrast, unit tests focus on individual components or units of code, testing them in isolation. Written primarily by developers, unit tests are essential for uncovering subtle issues within specific code segments, complementing end-to-end tests by ensuring each component functions correctly on its own.

Immediate Feedback from Unit Testing

QA teams benefit from the immediate feedback loop provided by unit testing, which allows for quick detection and correction of bugs introduced by recent code changes. This feedback enhances the QA team's confidence in the code's integrity and mitigates deployment anxieties.

Challenges of Unit Testing in Certain Frameworks

QA professionals face challenges with unit testing in frameworks like Angular or React, where unit testing can be complicated by issues with DOM APIs and the need for extensive mocking. The dynamic nature of these frameworks causes frequent updates to unit tests, making them quickly outdated. The React codebase is often not "unit test friendly," and time constraints make it difficult to invest in rewriting code for better testability. Consequently, testing often becomes a lower priority. The Angular testing ecosystem, particularly tools like Marbles for testing reactive functional programming, may be complex and not intuitive. Therefore, unit testing is typically reserved for small, pure utility functions.

Visual Testing/Screenshot Testing 

In front-end development, various methods are employed for maintaining visual integrity of websites. QA teams adopt methods beyond the informal "eyeballing" approach to ensure visual consistency with design specifications. This technique involves directly comparing the developed site with design files, like Figma files or PDFs, by placing them side by side on the screen to check for visual consistency.

QA professionals employ tools to simulate different screen sizes and resolutions. This effort is part of a broader user interface testing strategy, which helps to check if websites are responsive and provide a good user experience on different devices. Testing includes mobile-first optimization and compatibility with desktops. Automation is important for efficient and thorough visual verification.

Advanced testing frameworks, such as Jest, renowned for its snapshot testing feature, and Storybook for isolated UI component development, automate visual consistency checks. These tools seamlessly integrate into CI/CD pipelines, identifying visual discrepancies early in the development cycle. Automated visual testing ensures UI consistency and alignment with design intentions, improving front-end development quality. QA teams play a critical role in delivering visually consistent and responsive web applications that meet user expectations, improving product quality and reliability.

Achieving the desired software quality requires integrating a variety of testing strategies and leveraging QA expertise. Our partnership with an Israeli cybersecurity firm demonstrates these strategies in practice. Learn how we established a dedicated offshore team to handle extensive software testing, which resulted in improved efficiency and quality. This effort highlighted the value of assembling a focused team and the practical benefits of offshore QA testing.

Belitsoft, a well-established software testing services company, provides a complete set of software QA services. We can bring your web applications to high quality and reliability standards, providing a smooth and secure user experience. Talk to an expert for tailored solutions.

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