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E2E Testing Guide

What is End-to-End Testing? - A Complete Guide

May 22, 2024
 Rohith Ramesh Rohith Ramesh
Rohith Ramesh


End-to-end testing, often called E2E testing, constitutes a performance evaluation within the mobile app development cycle. The product's functionalities are tested from one end to another to ensure the entire application flow functions without setbacks. A fundamental objective of E2E testing is to offer developers insights into the user experience by simulating real-world scenarios. This approach mimics user interactions, thoroughly validating all essential components within the test environment.

This comprehensive blog explores the fundamental concepts, significance, advantages, tools, and frameworks of E2E testing within the dynamic landscape of mobile app development.

Read: Everything About Mobile End-To-End Testing

What is End-to-End (E2E) Testing?

End-to-end testing is a comprehensive testing technique that validates the interactions between different components of an application, including databases, servers, APIs, and the user interface. End-to-end testing aims to ensure that the entire system functions seamlessly and meets the desired requirements. It goes beyond individual unit testing and integration testing, as it assesses the application's behavior as a whole.

End-to-end browser testing is vital in identifying potential issues when different components interact. This includes scenarios like data inconsistencies, communication failures, or performance bottlenecks that can affect the overall user experience. By thoroughly examining the application's flow from start to finish, testers can gain valuable insights into the system's reliability and performance under various conditions.

What are the Types of E2E Testing Methods?

Depending on the end goal of the developers, there are two kinds of testing methods:

● Horizontal E2E Testing

This testing method tests the application across various platforms, interfaces, or applications that work together. It aims to ensure the seamless interaction and functionality of the application across different components. This type of testing is often conducted within the scope of a single Enterprise Resource Planning (ERP) system or a similar complex application.

Key Points:

  1. Cross-Platform Validation: Horizontal E2E testing ensures that the application functions correctly across different platforms, such as different operating systems, browsers, and devices.
  2. User-Centric Perspective: This approach is user-centric, simulating real-world scenarios where users interact with the application across various touchpoints. It aims to validate whether users can navigate through different parts of the app without encountering critical errors.
  3. Integration Testing: Horizontal E2E testing often involves integration testing, where the integration points between various modules, components, or systems are thoroughly validated.
  4. End to End Flow: Test scenarios cover End-to-End flows that span multiple components, applications, or systems. For example, it may involve testing the entire order-to-payment process in an e-commerce application.
  5. Usability and Compatibility: It checks the usability and compatibility of the application by considering how users experience the application in different environments.

● Vertical E2E Testing 

Vertical end-to-end testing, on the other hand, is conducted sequentially and hierarchically, focusing on testing the application's various layers or components from top to bottom. This type of testing ensures that each layer or component interacts correctly with the layers above and below it.

Key Points:

  1. Layered Validation: Vertical E2E testing is organized hierarchically, focusing on validating the functionality and integration of each layer independently and in relation to the entire system.
  2. Layer Interaction: It ensures that data and processes flow seamlessly between different layers, including the data layer, presentation layer, and business logic layer.
  3. Complex Applications: Vertical E2E testing is particularly suitable for complex applications with multiple interconnected components, where isolating and validating each layer's behavior is crucial.
  4. Moving Parts: This method is effective for applications with intricate internal workings and a high degree of interaction between different modules.
  5. Non-UI Systems: While horizontal testing often involves user interfaces, vertical E2E testing applies to non-UI systems, like backend services, APIs, or microservices.

Why Is End-to-end Testing Important?

End-to-end testing is crucial because it provides a holistic view of the application's performance and functionality. It helps detect system dependencies and maintains data integrity throughout the application. This testing method helps identify issues that might not be visible in unit or integration tests. By simulating real user scenarios, end-to-end testing ensures that the application will perform as intended in the real world, enhancing user satisfaction and reducing the risk of production failures.

How to Perform End-to-End Testing

End-to-end (E2E) testing is a key quality assurance activity that ensures a software application behaves as expected from start to finish. The goal is to mimic real-world scenarios and user interactions to detect system dependencies and ensure that all integrated pieces work together perfectly. Below is a detailed guide on how to carry out end-to-end testing effectively.

Step 1: Define the Testing Scope and Objectives

Before diving into testing, it clearly defines what needs to be tested and why it is crucial. This involves understanding the application's workflow, the critical business processes that the application supports, and the user interactions that need to be tested. It's also essential to define the success criteria for the testing phase, which will help assess whether the test cases have passed or failed.

Step 2: Plan the Test Cases

Once you have a clear scope, the next step is to plan the test cases. These should cover all the functionalities and user interactions with the application. When designing test cases, consider the following:

  • User Scenarios: Identify the most common user behaviors and scenarios that need to be tested.
  • Data Requirements: Determine the data needed for testing. This includes input data and expected outcomes.
  • Integration Points: Pay special attention to the interfaces and integration points where different system components interact.
Also Check: How To Make Your End-To-End Tests Last Longer and Run Smoother

Step 3: Set Up the Test Environment

A proper test environment is crucial for E2E testing. This environment should replicate the production environment as closely as possible to uncover any environment-specific issues. Ensure all necessary hardware, software, networks, and other system components are in place and functioning.

Step 4: Execute Test Cases

With your test cases and environment ready, begin executing the test cases. This step involves:

  • Running the Tests: Perform the tests according to the planned scenarios.
  • Monitoring: Continuously monitor the system's behavior and outputs.
  • Documenting: Keep detailed records of the test results, including any failures and anomalies.

Step 5: Analyze Test Results and Report

After testing, analyze the outcomes. Compare the actual results with expected outcomes to identify discrepancies. Any failures should be documented and reported to the development team for fixes. Successful tests should also be documented for future reference.

Step 6: Perform Regression Testing

Once issues are resolved, run regression tests to ensure the changes have not affected existing functionalities. This helps to maintain the stability and reliability of the software.

Step 7: Continuous Improvement

End-to-End testing is not a one-off activity but a continuous improvement process. Learn from each testing cycle. Refine your test cases, update testing methods, and improve the overall testing strategy to enhance software quality over time.

Read: The Importance of System Testing and End-to-End Testing

End-to-End Testing Success Metrics

To effectively measure the success of end-to-end testing, several key metrics should be considered:

1. Test Coverage:

This metric assesses how much the testing has covered all defined scenarios and requirements. High test coverage indicates a thorough examination of the application's functionalities.

2. Defect Density:

Defect density measures defects found per unit of the application's functionality or code. This metric helps understand the application areas that may require more focused testing or improvement.

3. Mean Time to Detect (MTTD):

MTTD is the average time to detect a defect during the testing phase. A lower MTTD is preferable as it suggests that the testing process effectively identifies issues.

4. Mean Time to Repair (MTTR):

MTTR is the average time required to fix a defect once it has been identified. Efficient processes and skilled development teams typically have a shorter MTTR, leading to faster release cycles.

5. Test Automation Percentage:

This is the percentage of tests automated versus those conducted manually. A higher automation percentage usually leads to more efficient testing phases, as automated tests can be run frequently and consistently without additional cost or time.

6. Pass/Fail Rate:

This straightforward metric tracks the number of tests that pass versus those that fail. A high pass rate indicates good application health, while a high fail rate may suggest systemic issues.

Best Practices for End-to-End Testing

  • Define Clear Objectives: Establish your goals with end-to-end testing, ensuring your chosen scenarios represent real-world use.
  • Use Appropriate Tools: Select testing tools that best fit your application's technology stack and testing requirements.
  • Create a Test Plan: Outline all the steps, from test case creation to execution and result analysis.
  • Automate When Possible: Automate repetitive and time-consuming tests to increase efficiency and accuracy.
  • Test in Realistic Environments: Ensure the testing environment resembles the production environment.
  • Monitor and Analyze Results: Regularly review test results for insights and potential improvements in the testing process.
  • Collaborate and Communicate: Encourage collaboration between developers, testers, and stakeholders to ensure that end to end testing aligns with user expectations and business goals.

By integrating these practices, you can enhance the effectiveness of your end to end testing, ensuring that your application is robust, reliable, and ready for production.

Check out: Guide to Accelerate and Strengthen Your End-to-End Testing Approach

Difference Between Functional Testing and End-to-End Testing

Functional testing involves testing specific features or functions of the software, focusing on validating the software against the defined specifications. On the other hand, end to end testing evaluates the system's overall functionality and performance in an environment that mimics real-world usage.

Aspect Functional Testing End-to-End Testing
Scope Limited to specific features or functions Covers the entire application flow
Environment Can be isolated or limited integration Mimics production environment
Dependencies Tests are independent of external systems Includes external systems and dependencies
User Perspective Focuses on software specifications Simulates real user scenarios
Execution Time Generally faster More time-consuming due to broader scope

Difference Between Integration Testing and End-to-End Testing

While integration testing evaluates the connectivity and data exchange between different modules or services within an application, end to end testing assesses the entire application's flow in a production-like environment.

Aspect Integration Testing End-to-End Testing
Scope Focuses on interactions between modules Covers the entire application flow
Environment Can be limited to specific integrated units Mimics production environment
Focus Validates data exchange and module cooperation Validates overall system performance and behavior
Complexity Less complex than E2E testing More complex due to broader scope

Also read: 7 Differences Between Integration Testing and End to End Testing

End-to-End Test Automation 

Incorporating end to end test automation is vital for improving the effectiveness of the testing process. End-to-end test automation allows for the execution of repetitive test cases without manual intervention, reducing the time and resources required for testing. By integrating end to end automation testing, teams can ensure consistent test execution, minimize human errors, and accelerate the feedback loop for developers, which is essential for agile and DevOps practices.

Advantages of End-to-End Test Automation

End to end test automation offers several advantages, making it an essential approach in modern software development and QA processes. End to end test automation provides faster feedback, increases test coverage, and enables continuous testing, all of which enhance app performance and reduce time-to-market.

End to end test automation allows for the execution of complex test scenarios more efficiently and consistently than manual testing. Automated tests can be run 24/7, providing continuous feedback on the application's performance and stability. This ongoing testing helps identify issues promptly, allowing development teams to address them before they escalate into major problems.

Furthermore, end to end test automation reduces human errors, ensuring accurate and reliable test results. As a result, developers can focus on building new features and improvements rather than repeatedly conducting time-consuming manual tests. Additionally, automated tests can be easily integrated into the Continuous Integration/Continuous Deployment (CI/CD) pipeline, facilitating a streamlined development process.

Also read: Exploring the top CI/CD tools for DevOps

End to end test automation is a crucial component of software testing that ensures the seamless functioning of an application throughout its user journey. End to end testing plays a pivotal role in delivering a high-quality user experience by pinpointing potential issues and optimizing app performance. Embracing test automation in the end to end testing process adds further value by increasing efficiency, accuracy, and scalability. As technology continues to evolve, integrating end to end testing and automation will remain essential for businesses seeking to maintain a competitive edge in the dynamic world of software development.

Challenges in E2E Testing

End to end testing is critical in software development, ensuring that applications perform as expected in real-world scenarios. However, this comprehensive testing approach comes with its own set of challenges:

  1. Effective Team Communication and Collaboration: End to end testing often requires heightened levels of communication and collaboration compared to manual testing. This encompasses discussions about test automation objectives, scope, and selection of tools with various stakeholders, including developers, business analysts, and project managers.
  2. Selecting the Right Testing Tool: Choosing the right one is crucial with many testing tools available. It's vital to conduct research and consider the application's specific requirements under test, as a mismatch in tool selection can lead to test automation failure.
  3. Demand for Skilled Resources: Contrary to the belief that manual testers can easily transition to automated testing, end to end testing demands specific technical skills for designing and maintaining the test framework. The need for skilled resources with programming capabilities and a deep understanding of test automation tools is critical.
  4. Choosing an Appropriate Testing Approach: Determining the correct testing approach is fundamental. This involves decisions about reducing effort in test script implementation and maintenance, ensuring the longevity of test suites, and generating useful test reports.
  5. High Initial Investment Cost: The initial end to end testing phase involves significant costs, including framework design, tool selection, and possible licensing fees. Despite the long-term benefits, the upfront investment can be a barrier.

Understanding and addressing these challenges early in the testing process can lead to more effective and efficient end to end testing strategies, ultimately contributing to the success of software projects.

A Few End-to-End Testing Tools for Seamless Software Quality


testRigor is an end to end testing tool that allows you to view complex test executions and is an entirely cloud-hosted system. It lets you create seamless test automation for manual and hybrid QA testers since it is no code. It allows them to focus on testing new features and edge cases instead of focusing on repetitive tasks.

testRigor also supports cross-platform and cross-browser testing for web and mobile, API functionality, phone calls, and SMS. The tool can also record and playback and autonomously create test cases.


Mabl is an end to end testing tool that lets you execute and create test scripts from a single platform. Mabl fetches data from the user's actions allowing users to complete software testing using scriptless code.

Mabl provides E2E testing using integrated UI and API tests through a single platform. The tool validates status code responses, body, and header values allowing you to execute automated API testing. It integrates with apps like Bamboo and Azure Pipelines and notification systems like Microsoft Teams and Slack.


Autify lets you manage, create, and execute complex test cases and have thorough reports on completed tests - this web and mobile app automation tool provides visual regression testing coverage. This end to end testing tool identifies the differences in your app and runs tests without requiring maintenance. You can use the tool's Chrome extension to record interactions.

It supports cross-browser testing and lets you test on real devices, allowing you to provide a seamless user experience. It integrates with Jenkins, Slack, and TestRail.

How HeadSpin's Advanced Testing Solutions Empower Businesses to Optimize End-to-End Mobile App Test Automation

HeadSpin revolutionizes the landscape of E2E  mobile app test automation by offering a comprehensive suite of tools and services that streamline the testing process and elevate the quality of web, mobile, video, and audio experiences across the entire application lifecycle.

● Advanced Testing with the HeadSpin Platform

At its core, the HeadSpin Platform simplifies the intricacies of end-to-end testing. It empowers development teams to ensure impeccable quality in every facet of their applications. From initial development to post-launch optimization, HeadSpin's comprehensive approach covers the entire app development and usage journey.

● Data-Driven Insights with AI-Powered Analysis

HeadSpin's E2E testing tool isn't just about conducting tests and generating invaluable insights. Through its data-rich approach and AI-powered analytics, the tool provides high-quality, actionable insights that empower you to optimize and perfect your digital experiences. From identifying performance bottlenecks to pinpointing usability issues, HeadSpin's analytics drive data-driven decision-making, enabling you to refine your application precisely.

● Global Device Cloud for Seamless App Test Automation

HeadSpin's distinctive strength lies in its extensive global device infrastructure, housing thousands of SIM-enabled devices worldwide. This expansive device network enables seamless app test automation, allowing you to test your application's compatibility, performance, and functionality on various real devices. This global reach ensures that your app is validated under a wide range of network conditions, locales, and user scenarios, ensuring it performs optimally in every corner of the globe.

● Versatile Deployment with the HeadSpin Appliance

The HeadSpin Appliance introduces a novel dimension to testing infrastructure. Featuring a portable, secure, and temperature-controlled environment, the appliance is an ideal setting for conducting tests on various compatible applications. Whether deployed in the cloud, on-premises, or anywhere else, the appliance offers a standardized and controlled testing environment that ensures consistent and reliable results.

Summing Up

To sum it up, E2E testing is a valuable form of testing that will allow your business to benefit from a comprehensive and highly developed app. When you conduct tests on your app, make sure to use E2E testing so that maximum coverage is ensured. It'll also save you a lot of time and money.

With AI-powered insights, HeadSpin empowers you to fine-tune your app's performance, functionality, and user experience while streamlining your testing process.

Harness the capabilities of HeadSpin to optimize your testing strategy and deliver an app that exceeds expectations.

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Q1. What is end-to-end testing in Agile?

Ans: End to end testing is software testing that tests flow from beginning to end instead of only testing individual steps. It's possible to test an application and its connection with other applications as the user experiences it by performing end to end tests.

Q2. What is the difference between end-to-end testing and system testing?

Ans: System testing validates the system as per specifications. It tests software functionality, and you run it manually and through automation.

End to End testing tests the software flow from end to end. It requires knowledge of the interconnected system, and you run it manually.

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