Integration testing, system testing and End-to-End testing

-

Difference between Integration testing, system testing and End-to-End testing


Integration Testing

Integration Testing is a level of software testing where individual units or components are combined and tested as a group. The goal is to identify and fix any issues in the interactions between integrated modules or systems.

This testing comes after Unit Testing and before System Testing in the software testing life cycle.

Why is it Important?

Even if individual modules work perfectly in isolation (after unit testing), problems can still occur when:

  • Data passed between modules is incorrect.

  • Modules call each other incorrectly.

  • Interface mismatches exist.

  • External systems respond unexpectedly.

Integration Testing helps ensure that the combined behavior is correct.

Scope of Integration Testing

        ·       Tests the interfaces, data flow, and interaction logic between connected modules.

        ·       Checks both synchronous and asynchronous communication.

        ·       Includes internal integrations (e.g., between classes/modules) and external integrations (e.g., APIs, databases, third-party services).

Examples of Integration Testing Scenarios

1.Banking App:

When transferring funds, the Transaction module must integrate correctly with the Balance module, Notification module, and Audit Log module.

2.E-commerce:

The Cart module must correctly pass items and prices to the Payment module, which then calls the Order Confirmation module.


System Testing

System Testing is the phase where the whole software is tested as one complete system to ensure it meets all requirements. It comes after Integration Testing and checks both functional and non-functional parts like performance and security. The goal is to verify the software works correctly from start to finish in real-world scenarios.

Why System Testing is Important:

  • It validates the complete and integrated software product.
  • Ensures the software is ready for deployment by simulating real user conditions.
  • Detects issues that may not surface during unit or integration testing.
  • Helps deliver a quality product that meets both technical and business expectations.
Example of System Testing

Imagine testing an online shopping website. System testing checks the entire app to make sure everything works properly from start to finish.

What’s tested:

  • Can users log in, search for products, and place an order?
  • Does payment work with all methods?
  • Is a confirmation email sent?
  • Does it work on different devices and browsers?
  • Can the system handle many users at once?
  • Is user data safe during login and payment?
System testing is important because it checks the entire software as a whole to make sure everything works correctly. It helps find issues in real-world user flows like logging in, making payments, or using the system on different devices. By testing both functionality and performance, system testing ensures the software is ready for release and works as expected for users.



End to End Testing 

End-to-End (E2E) testing is a testing approach where the complete software application is tested from beginning to end, just like a real user would use it. It ensures that all parts of the system including the user interface, backend, database, and third-party services work well together. The main goal is to confirm that the entire user journey, from login to final output, functions correctly and mirrors real-world scenarios.

Why it is Important?
End-to-End testing is important because it ensures that the entire application works as a complete system from the user's perspective. It helps catch issues that may not appear during unit or integration testing, such as broken workflows, miscommunication between components, or failure in external services. By testing real user scenarios, E2E testing helps ensure a smooth and reliable experience for users, reduces the risk of bugs in production, and builds confidence before releasing the software.

Scope of End-to-End (E2E) Testing:
The scope of E2E testing covers the entire workflow of an application—from start to finish. It includes:

  • User Interface (UI) – Testing how users interact with the application.
  •  Backend Services – Ensuring correct data processing and communication.
  •  Databases – Validating data storage, retrieval, and integrity.
  •  External Systems – Verifying third-party integrations like payment gateways, emails, or APIs.
  •  User Scenarios – Simulating real-world actions, such as login, purchasing, or submitting a form.
  •  End-to-End Flows – Making sure that each step in a business process connects and functions properly.
Examples of End-to-End (E2E) Testing:

Example : E-commerce Website (e.g., Amazon)

Scenario: User purchases a product
Steps:

  • User logs in
  • Searches for a product
  • Adds the product to the cart
  • Proceeds to checkout
  • Enters shipping and payment info
  • Confirms the order
  • Receives a confirmation email

This tests the full purchase flow across UI, backend, database, and external payment/email systems.

In short, it tests everything that a user might touch or that affects the user experience across the whole system.



Difference between Integration, System and End-to-End Testing

Type

Focus Area

Scope

Test Level

Example Scenario

Integration Testing

Interaction between modules

Limited to connected modules/components

Low–Mid level

Login module passes user ID to dashboard

System Testing

Entire system functionality

Complete system as a whole

Mid level

Online shopping features tested together

End-to-End Testing

Full user flow across systems

Real-world workflow + external systems

High level

User places an order and tracks delivery




In short, Integration testing ensures that individual modules work well together, system testing validates the complete and integrated software against requirements, and end-to-end testing verifies the entire application flow from start to finish in real world scenarios. Together, these testing levels help deliver a reliable, high-quality software product that meets user expectations.

Comments

Post a Comment

Popular posts from this blog

Non-Functional Testing

-
Non-Functional Testing Non-functional testing  is an important part of software testing that checks how well the system works rather than what it does. It focuses on quality aspects like  performance ,  security ,  usability , and  reliability  to ensure the software is stable, efficient, and ready for users. Types of Non Functional Testing in Software Testing Non-functional testing types encompass a broad spectrum of testing types, each evaluating the software’s performance and usability. 1. Performance Testing Assess how fast and responsive the application is under different conditions. It measures metrics like response time, load time, and throughput to ensure smooth operation under typical usage. 2. Load Testing Simulates expected user traffic or transaction levels to check for performance bottlenecks. This helps identify whether the application can handle the anticipated load before going live. 3. Stress Testing Pushes the system well beyond normal ope...
Read more

Black Box Testing and White Box Testing

-
Black Box Testing and White Box Testing Black box and white box testing are distinct methodologies with opposing objectives. However, they can complement each other to improve testing effectiveness. Black box testing evaluates an application from the user's perspective, while white box testing examines the code and internal design. Black box Testing Black box testing  is a way of testing software without looking at its internal code or design. Testers check if the software works as expected by using the requirements and specifications. They enter data, watch the outputs, and see how the system responds, including how fast and reliable it is. This method can be used at many levels of testing, like unit, integration, system, and acceptance testing, but it’s mostly used in higher-level tests. Testers don’t need coding knowledge—they just focus on whether the software does what it should from the user’s perspective. It’s also called specification-based testing or closed box testing bec...
Read more

Use case vs Test Case

-
Use case vs Test Case What is a Use Case? A  use case  is a common concept in software development that explains how a user interacts with a system to achieve a specific goal. It shows step-by-step what happens during the interaction, including inputs, outputs, and expected behavior. Use cases can be written as text or shown in diagrams, helping teams understand what the system should do from the user's point of view. What is a Test Case? A  test case  is a set of instructions created by testers to check if a specific feature or function of a software application works correctly. It includes the test inputs, conditions, and the expected results. Test cases help find bugs and ensure the software is reliable and meets the requirements. Each test case should be clear, linked to the correct feature, and well-documented. Managing test cases properly is key to successful testing and delivering a high-quality product. Difference between Use Case and Test Case Use case Test ...
Read more