What is cross-browser testing?
Cross-browser testing refers to the process of checking if a web application works as intended, across various browsers on devices running major operating systems (OSes).Cross-browser testing is essential to ensure that a web application's performance is the same irrespective of the device it's accessed from, barring location-based server dependencies.
Why cross-browser testing is needed
With the advancement in backend technologies, development tools, servers, and the internet as a whole, web applications are expected to cruise through all their operations without a hiccup. Apart from the testing required to check web applications for any errors, dedicated testing is essential to ensure that they work flawlessly across the plethora of modern and legacy systems.
Web3 is widely accepted as the future of the internet, and development for web3 applications requires dedicated testing to ensure there are no errors. Cross-browser testing is vitally important to the proper functioning of these applications on different hardware and software
Choosing devices for cross-browser testing
Choosing the different devices to perform tests on is the most important step in cross-browser testing. For optimal results, the following set of devices need to be tested:
Virtual machines
Virtual machines are emulations/virtualizations of computer systems that come with customizable hardware and software that simulate the most-used types of desktop PCs. Different versions of various browsers can be opened inside the virtual machine, just as one would in the real world, to test if the web application performs flawlessly on systems. Testing on virtual machines comes with its own set of limitations, however.
Desktop systems
For efficient cross-browser testing, the performance of web applications has to be assessed on desktop-class browsers. Desktop systems aren't bottlenecked by the limitations of virtual machines, and also include all the functionalities of the application that aren't available on mobile browsers.
Mobile devices
With the sharp rise in use of mobile devices around the world, web applications need to be tested on actual mobile devices that are connected to a desktop system or laptop. During the final stages of testing, the web application can be checked directly on the mobile device browser by accessing its url.
When should cross-browser testing be performed
Cross-browser testing is a part of compatibility testing and falls under the non-functional testing that's carried out towards the end of the software testing lifecycle (STLC). Generally, cross-browser testing is one of the final sets of tests performed, once a web application has already been tested to work efficiently in virtual environments.
Once the application is found to be working flawlessly in these environments, it's tested on different virtual machine configurations, mobile simulators/emulators, and actual devices. Ensuring that the web application works properly is a criteria that needs to be fulfilled before making the software available to end users, as pushing a buggy application live can become time-intensive to fix.
Advantages of cross-browser testing
There are many advantages to performing cross-browser testing, but a few of the prominent ones are:
Better coverage
Checking the compatibility of applications across different types of devices can lead to better coverage. Ultimately, the goal of cross-browser testing is to check how the application performs on different devices, to maximize compatibility.
Faster testing
When automated, testing can be carried out for every device in succession. Testing times can be further reduced by employing parallel testing for cross-browser testing, as testing for multiple devices can be carried out simultaneously, based on the availability of bandwidth.
Accurate results
An error identified for a particular device model can affect thousands of users. Working on a fix for the error can make it easier for the team to address similar errors on other devices. Cross-browser testing can assist in providing accurate results for each particular device, so that it's easier for the development team to work on fixes.
What makes cross-browser testing challenging?
There are a few things that need to be addressed for cross-browser testing:
Multiple device configurations
Cross-browser testing is a time-consuming process, as it requires testing on various browser and OS combinations. The testing is carried out in succession for each specific configuration, and automation is the preferred mode of testing, as there can be hundreds of combinations.
Versions
These hundreds of device configurations become manifold and can easily creep into the thousands when different versions of individual browsers and OSes are taken into account. Automated cross-browser testing is the best way to reduce the time taken for testing each device.
Display resolutions
Web applications are accessed on many different devices at any given time, and each device comes with a different display resolution. For each of these resolutions, the web application needs to resize automatically, so that the contents display and perform properly everywhere.
Resources
Multiple bouts of extensive testing for each configuration, even if automated, takes up a considerable amount of time and resources.
Understanding the scale of cross-browser testing
Cross-browser testing focuses on testing web applications on different browser and operating system combinations. To understand the scale of the different configurations to be tested, let's look at the hypothetical scenario of launching a web application.
For the cross-browser testing part, the application needs to be tested on various popular browsers, like Firefox, Chrome, and Safari. Furthermore, all these browsers run on different versions of the operating systems for desktop—macOS, Windows, and Linux—and mobile—iOS and Android. But testing these three browsers running on five operating systems doesn't guarantee coverage of the entire user demographic.
Each user accessing the web application might be using a unique combination of browser and operating system versions. It's essential to check all the different combinations of browsers and operating systems to ensure compatibility everywhere.
In the case of large-scale applications that cater to millions of users, the number of combinations that need to be tested is proportional to the scale of the user base. Generally, cross-browser testing is performed on thousands of browser and device combinations.
Steps for comprehensive cross-browser testing
Finalize the functionalities to be tested and create or select the respective test cases based on all possibilities.
Choose manual or automation testing and configure parallel testing, if available.
Select all the device and browser combinations for optimized cross-browser testing.
Execute the test cases on the different environments discussed in the previous step.
Analyze the test reports extensively and collaborate with the development team on fixes.
Repeat steps 1 through 5 till no more fixes are necessary.