End-To-End Testing

Lifecycle of E2E

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An E2E testing mechanism has four components: test planning, test design, test execution, and result analysis. 

• Test Planning: We specify the critical tasks and the resources required in this phase.
• Test Design: We define the test cases and analyze all the risks in this phase.
• Test Execution: We execute all the test cases obtained in the previous stage.
• Result Analysis: This is the final phase, and here we analyze the results and perform any additional tests necessary.

Methods of E2E Testing

We perform the E2E testing using one of these two methods.

1. Horizontal E2E testing: In this type of E2E testing, we simultaneously test across the content of multiple subcomponents of the application. For instance, in the case of an E-commerce website, there are numerous subcomponents like payment details, order details, inventory list, and many more, so we scan through all these components simultaneously.
2. Vertical E2E testing: Contrary to horizontal testing, in vertical testing, we test the components of the application in sequential hierarchical order. To ensure better quality and a convenient end-user experience, each subcomponent is sampled from the beginning to the end. We generally use Vertical E2E for critical components of an application.

Why is E2E necessary

As discussed earlier, the software can get very complex with multiple integrated systems, including databases and other subcomponents. Making the application workflow reasonably complicated, we already know E2E works on each component and checks if it works accurately.

• Backend: Using E2E, we can verify the database's functionality and the application's backend layer. Backend and database are the core of any application since all the capabilities depend on the backend layer.
• Multi-tier System: E2E is necessary for applications with complex workflow structures to verify overall functions and the interaction between individual components of the application. 
• Distributed Environment: Cloud environment-based applications require E2E testing.
• Consistent User Experience: E2E ensures cross-browser compatibility, i.e., it ensures the application provides a user experience that works across multiple devices, environments, and platforms.

When to Perform E2E

For applying end-to-end testing, we have many scenarios. Let's look at an example.

Developers and designers create a list of all the UI, functions, or features needed before testing. For finding dependencies, flaws, and inaccuracies, we should track the data flow between systems. Before testing, teams must also prepare the conditions – factors that may change any interface options.

Each review becomes a test of the completed design when we regularly conduct E2E testing on finished products and systems. We go for a second test if the system does not expect output or any discrepancy or error. The team records and analyzes the data to determine the issue's origin, then fix and re-test them in this case.

Main Challenges in E2E

Detecting bugs in a complicated workflow is incredibly challenging. Now we will go through the two significant challenges:

1. Creating workflows: We run the test cases in a particular sequence for examining an app's workflow. As they navigate through the app, we must match this sequence and the path of the end-user. Creating test suites for checking this workflow can be taxing, especially since they usually involve developing and running thousands of tests.
2. Accessing Test Environment: It is easy to test apps in dev environments. Every application, however, must be tested in client or production environments. The chances are that prod environments are not always available for testing. Local agents have to be installed by Testers and log into virtual machines even when they are. Furthermore, testers must prepare for and prevent system updates from interrupting test execution. Test on an actual device cloud is the best way to access an ideal test environment. If in-house device laboratories are not an option, consider using a service like BrowserStack, which provides a cloud Selenium grid of 2000+ actual devices and browsers for testing. Access a device that users will navigate an app and ensure that the app functions flawlessly in actual user conditions.

Best Practices for E2E

To ensure smooth testing of an application using E2E, it is essential to consider the following listed points:

1. Always prioritize the end-user.
2. Test cases should be used such all the unusual test cases are ignored, and only general test cases are considered.
3. It is crucial to maintain a structure while performing E2E
4. The environment should be such that it is accessible every time with minimal setup.

FAQs

1. What should be tested in E2E?
   In E2E, we test the entire application from the beginning to the end to ensure the application behaves as expected.
    
2. Why is E2E necessary?
   E2E can handle very complex applications with branched subcomponents with ease and with accuracy
    
3. What is the difference between Functional and End-To-End tests?
   Functional tests are limited to a single piece of code or application at a time whereas, E2E can be performed on multiple components simultaneously.

Key Takeaways

This Blog covered all the necessary points about End to End testing of any application, discussing in-depth its functionality and methods of the appliance. We further examined the challenges faced and why it is necessary.

Recommended Readings:

• Sanity Testing vs Smoke Testing
   

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