Visual regression testing is a very important parameter for verifying the proper placement of all the important elements present in modern applications Irrespective of update changes. With the help of visual regression testing, the testers can also ensure that the elements remain in their designated position and functional irrespective of the device and screen resolution. It is also possible to integrate automation testing with visual regression testing to further boost the efficiency of these test cases. The application developers can also use modern technologies like Agile methodologies to improve the coordination between the testing and development teams of the company. Visual regression testing is crucial when working with mobile applications as it is one of the most diverse markets.
So with this article, we will discuss how companies can implement visual regression testing for PDF files. We will also discuss some of the most important points to justify the visual regression testing of PDF files and some of the best practices in this segment.
A Generalised Idea of Visual Regression and Automation Testing
The term visual regression identifies test cases that check the proper placement of user interface elements irrespective of updates. In simple terms, it ensures that all the old elements are functional and in their proper position irrespective of adding new elements. Some of the common errors that can arise in this segment include the misplacement of elements, omission of elements, and complete crash of the app infrastructure. All these errors can harm the user experience and harm the brand image of the company.
Since visual regression is a repetitive process that needs to be performed after every app update, it can benefit a lot from the integration of automation testing. This is an advanced process that eliminates human involvement by emulating human interactions through predetermined test parameters. These parameters are supplied by text files that can be changed according to the requirements of the app project. While implementing visual regression testing, test automation can benefit the app project in the following ways:
- Since it will conduct all the repetitive test cases, the development and testing teams can focus on the creative areas. For instance, they can work together to create an innovative feature for future aversion.
- With test automation, it is possible to integrate various advanced technologies like parallel test execution, real-time activity logs, and agile methodologies to improve the quality and efficiency of app projects.
- Since test automation is completely executed by the system, it is devoid of errors that can arise due to human involvement. Moreover, it can run test cases practically all the time which is beyond human abilities.
- Using automation testing, the app development company will benefit a lot in the long run as it will help to eliminate the resources required for maintaining a manual testing team.
Need to Implementing Visual Regression Testing on PDF Files
Visual regression testing is crucial for the UI elements of web apps. However, the new automation testers and developers might be skeptical about performing visual regression testing on PDF files. So for simplicity, we have created a list mentioning some important factors that justify implementing visual regression testing on PDF files:
- This process will allow us to maintain the visual consistency of all the PDF reports, documents, and other important information. This process will in turn ensure that all the data in these PDF files look polished and professional irrespective of the device.
- Whenever app developers are working with PDF documents that are related to industries including legal, finance, and health care, there are certain regulatory standards that they must comply with. Visual changes in these documents can cause misinterpretation of the data and breach these standards.
- Maintaining the visual consistency of PDF files will ensure that the customers can have the best end-user experience while accessing these files. So, they can extract the required information irrespective of their device.
- Some of the other important factors that visual regression testing helps to ensure include bug identification and version control. Visual regression testing helps to identify unintentional changes that may be implemented in the multiple versions of a PDF file. On the other hand, it also detects the bugs that might have slipped through the development process.
LambdaTest and How it Benefits Visual Regression Testing
LambdaTest has recently ruled out an update that allows the developers to integrate visually vigorous testing while working with PDF files. For the general introduction, we can say that LambdaTest is an AI-powered test execution and orchestration platform. The cloud infrastructure allows the developers to execute real device testing on thousands of devices through remote servers. This platform can boost the accuracy of the test reports by integrating multiple instances from evolution software and real devices.
While implementing visual regression testing, the LambdaTest real device testing cloud will benefit the process in the following ways:
- This platform enables the parallel test execution of visual regression test scripts. This means that the app developers can initiate thousands of different test instances on different configurations and machines at the same time. Using this feature, it is possible to complete the entire test suite for complex applications within a few days.
- While implementing visual regression testing, LambdaTest maintains a real-time activity log to keep track of all the test cases including the failed and successful ones. The app developers can also later use this data for referencing whenever they encounter some known issues.
- LambdaTest uses its SmartUI for executing visual regression test cases. This technology can quickly detect even a minor change between the uploaded screenshots and the baseline images. It also has a smart algorithm to automatically detect the changes and highlight them in the test report. So the app developers can easily use this report to navigate to the faulty elements during the troubleshooting process.
- LambdaTest has an extensive support team that can be reached over the phone, through live chat, and also through the mail. So the new testers and developers can use these methods to get detailed knowledge about all the features and tools available with LambdaTest. It also has an open community of enthusiasts who can discuss among themselves multiple issues related to application development.
- Finally, the test report of LambdaTest is very intuitive and easy to understand. This is because it integrates various videos, screenshots, and test activity logs for ease of understanding. The interface of LambdaTest will automatically capture these data whenever there is an issue during the test execution process
Executing Visual Regression Testing of PDF Files
The app testers can easily perform visual regression testing of PDF files by using the SmartUI of LambdaTest. Based on our research and understanding we have mentioned all the prerequisites and steps in the intended order:
Prerequisites:
- The application testers must get themselves familiar with the ATTP APIs. This is because LambdaTest will use these APIs for executing the test cases on PDF files.
- The application developers have to set up a new LambdaTest account through the official website. It is a very simple process as it involves following a few on-screen instructions. Then, the developers have to purchase the license and navigate to the LambdaTest SmartUI. Using the license and other credentials, developers have to log in on this web page.
The final step in this process is to obtain the “LT_ACCESS_KEY” and “LT_UERNAME”. For this step, the developers have to click on the access key button that will be located at the top right corner of the official dashboard.
Creating the SmartUI Project
The first step in this process is to create a new SmartUI project for running the visual regression test cases on the PDF files system. For this process, the application developers have to follow the following steps:
- Firstly, it is important to navigate to the official page of SmartUI projects.
- Next, the application developers have to click on the new project button that they will find on the official page.
- The developers need to specify their target platform type as a PDF.
- Following the specification, the system will automatically ask to name the project and designate its approvers. The system will also ask the developers to add the tags but it is an optional process that can be skipped.
- After entering all the required data, the developers have to review these data before finally clicking on the submit button.
- After the project has been successfully activated by the system, the developers have to retrieve the project token from the app. This token will look as mentioned below:
projectToken = “123456#1234abcd-****-****-****-************”
Integration of PDFs Using API
Now after setting up the SmartUI project, it is time for the app developers to upload their local PDF files to the LambdaTest API. This process will automatically generate a build as it will capture screenshots of every page in the PDF:
- The first step is for the tests to retrieve their “URL Endpoint” after the activation of the enterprise plan.
- Now, it is time for the app developers to mention the project token that they have retrieved in the previous part of this guide. This is because, with the help of this token, it is possible to not only upload the PDF files but also validate the visual regression testing project.
- Next, it is time to use the “pathToFiles” variable as it will add the path to the PDFs that will be uploaded. In case the application developers are working with multiple PDFs, the system will automatically number them in chronological order.
- The following code will configure the PDF Visual Regression Environment:
from pdf2image import convert_from_path
From PIL import ImageChops
def pdf_to_images(pdf_path):
return convert_from_path(pdf_path)
def image_diff(image1, image2):
return ImageChops.difference(image1, image2).getbbox()
def main():
baseline_pdf_path = ‘baseline.pdf’
test_pdf_path = ‘test.pdf’
baseline_images = pdf_to_images(baseline_pdf_path)
test_images = pdf_to_images(test_pdf_path)
num_pages = min(len(baseline_images), len(test_images))
for page_num in range(num_pages):
diff_bbox = image_diff(baseline_images[page_num], test_images[page_num])
if diff_bbox is None:
print(f”Page {page_num + 1}: No visual differences found.”)
else:
print(f”Page {page_num + 1}: Visual differences found.”)
if __name__ == “__main__”:
main()
The Final Verdict
By implementing visual regression testing on PDF files, the application developers can massively boost the quality of the data that they are forwarding to their customers. Moreover, the integration of automation testing further boosts the efficiency of the visual regression test cases. However, to utilize the full potential of this integration, the testers should constantly update their knowledge about all the revolutionary innovations in this segment. It is also vital to constantly collect adequate information about the requirements of the target audience. Using this data, the developers can implement all the required changes to maximize their audience reach. Finally, by choosing an automation framework that can complement the project and its requirements, automation testers can boost their productivity.