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System Testing vs Integration Testing with Types and Advantages

System Testing vs Integration Testing with Types and Advantages

Every software undergoes multiple quality checks in the software development life cycle (SDLC). Such analysis ensures a high-grade product, leaving no scope for future issues. But it is easier said than done. While the agile framework improves communication and collaboration in the testing process, many experienced testers still encounter uncertainty during the testing process.

They know integration testing comes before system testing but find it difficult to go through the process sequentially. It is usually because multiple updates keep emerging. And this the exactly where the debate of System testing vs Integration testing arises.

Point to Note: The testing stages follow the below sequence: Unit testing, Integration testing, System testing, and Acceptance testing.

Every module requires individual attention before they integrate to make a system. Any new change could incite non-functional or functional issues. Hence, following the right testing procedure is integral to avoid mishaps in the system’s build.

We understand some of these phrases might sound alien to you. But because both these tests are integral in SDLC, you need to know the why, how, and when of the System and Integration testing. This article will help you understand the basic definitions and requirements of both tests for your next sprint.

What is System Testing?

A type of Software testing, System testing comes at the third level after Unit testing and Integration testing. The goal of the system testing is to compare the functional and non-functional features of the system against the user requirements.

Once all the sub-systems or modules integrate to build one application, testers perform System testing to check for potential functional and non-functional irregularities. Overall, System testing checks for the system’s design and behavior as per customer expectations. It is a black box testing technique.

Often, your QA team will rely on System Requirement Specifications (SRS), Functional Requirement Specifications (FRS), or a mix of both. We will discuss these two options later in this blog.

Types of System Testing

System testing covers the end-to-end analysis of a software application in terms of its functionality and user experience. Hence, you can categorize it into two parts—functional and non-functional.

Functional Testing

Functional testing validates the functional aspects of a software system against the user requirements and functional specifications. It checks for user experience or interface, API integration, database, security and privacy, and server communication, as mentioned in the user document.

One example of functional testing is checking for the login functionality using the right credentials. The system should not allow you to sign in if your username and password are wrong or not present in the database.

Non-Functional Testing

Non-functional testing checks for non-functional aspects of software, such as performance, reliability, usability, and application readiness. It intends to assess a system’s performance per the non-functional conditions that never appear in the functional tests. Often, non-functional testing is important to check for security, application load capability, and utility to measure user satisfaction.

One example of non-functional testing is checking for the number of users the system can handle at a time. It helps to determine the performance and usability of the system under high traffic.

Advantages of System Testing

There are a few advantages of System testing that helps uncover possible application errors that bypass the Unit testing and Integration testing stage.

  • Every system requires complete testing, which happens in the System testing stage.

  • System testing simulates the production environment to allow testers and stakeholders to get a full view of users’ responses.

  • It eliminates or reduces the troubleshooting instances following the application deployment.

  • System testing uses multiple (positive and negative) test cases to identify functional issues.

  • It encompasses technical and business requirements testing.

  • Testers only need to know the expected outcome of the test cases; they do not need coding knowledge to perform System testing.

When Should You Perform System Testing?

The primary goal of System testing is to check the final build after the integration of all the components. Ask your team to perform System testing:

  • During the development of new software versions/updates

  • During the initial launch of the application

  • After Unit and Integration testing

  • When you add new functional or non-functional requirements to the system

Usually, testers rely on System Requirement Specifications (SRS), Functional Requirement Specifications (FRS), and sometimes both to perform System testing.

SRS documents the technical features and behavior of a software application. FRS describes the functioning and different components of the system. Majorly, FRS does not require deep technical information and is useful for all levels of stakeholders.

What Tests are Carried Out in System Testing?

System testing includes multiple tests, such as:

  • Recovery Testing: As the name suggests, a recovery test checks the system’s ability to recover from downtime. It intentionally forces the system to fail and test the recovery process.

  • Load Testing: Testers perform load testing to determine the behavior of a system under extreme user load or high traffic volume.

  • Security Testing: Security testing examines the software’s potential vulnerabilities and risks to identify its weakness. It checks for the product’s counterattack response and corrective measures by exposing it to threats.

  • Performance Testing: A performance test takes place simultaneously throughout the testing process to measure the software’s responsiveness, scalability, and reliability.

  • Regression Testing: Regression test checks if the latest updates affect the existing software application functionalities.

  • Interoperability Testing: Interoperability testing aims to check if the system is compatible with third-party tools or applications.

  • Hardware/Software Testing: This type of testing examines the interaction between software and hardware to check if the data transfer or communication between the two is without issues.

What are the Approaches to System Testing?

System testing has two approaches—requirement-based and use-case-based—both have their advantages. The former relies on project documentation as the primary criteria, whereas the latter focuses on using user behavior as its benchmark. The choice of your approach decides if you need Alpha or Beta testing, both of which come under Acceptance testing.

How is System Testing Done?

Follow the below steps to perform System testing:

  • Test Plan: Create a test plan, including test cases and scenarios

  • Test Data: Gather or generate test data to perform automated and manual testing

  • Perform the Test: Conduct the test using the above test plan and data.

  • Measure Results: Match the real outcomes with expected results to identify issues

  • Report Bugs: Raise the bugs to the concerned team or individual to get a fix

  • Repeat: Go through the steps repeatedly till no faults remain undiscovered

Next, in System testing vs Integration testing, we will cover the latter to understand its need, advantages, and approaches.

What is Integration Testing?

Integration testing follows Unit testing and comes before System testing. It checks for compatibility between multiple modules as they logically integrate and are tested as a group. Integration testing aims to catch possible defects in the modules after their integration; such defects might occur because of data transfer incompatibility. It consists of the white box, black box testing, and grey box testing per the requirements.

The prime focus of Integration testing is to test for seamless data transfer and communication between components. It is also referred to as I&T (Integration and Testing), String Testing, and Thread Testing.

Advantages of Integration Testing

Although every module undergoes individual testing for fault detection, it is still necessary to check how they function together. Some defects can still arise as these modules start communicating with one another. Thus, Integration testing is advantageous in below aspects:

  • Integration testing is essential to check for interaction between modules and database for error detection

  • It uncovers interface errors among modules

  • Integration testing is effective in executing user-based scenarios

  • It covers a large part of Adhoc testing

  • Integration testing helps you to perform Regression testing on some of the important connection points

  • Compatibility issues among modules might raise faults, which are only visible during Integration testing

  • Integration testing checks for software and hardware compatibility

When Should You Perform Integration Testing?

Typically, your team will perform Integration testing during the development and integration stage of software modules. However, there could be some instances where modules are still not ready for testing. Yet, we recommend you start your Integration testing:

  • In order to analyze the performance of several integrated modules

  • To check if the data transfer between these modules has any issues

  • For checking if integration between software and hardware is proper

What Tests are Done in Integration Testing?

There are a few tests your QA team will perform while conducting Integration testing. But we will discuss three tests that most influence Integration testing to check communication and flow between the modules.

  • Data Flow Testing: This type of testing analyzes data flow across an application or software. It checks for data transfer between modules and highlights issues related to information transition.

  • Control Flow Testing: This comes under White box texting and uses the software’s control flow as the testing model. Control flow testing checks for the transfer of control from one module to another as users move forward in the application.

  • State Transition Technique: A type of black box testing, State Transition analyzes the changes in output as input differs for the application under test. It helps determine the behavior of different modules functioning together for different input conditions.

Approaches of Integration Testing

There are four Integration testing approaches that you can implement as per your need:


Big Bang Approach

Under this approach, the modules integrate right after their development is over. Hence, the Integration test is done on the entire system. The Big Bang approach is useful when modules are ready and integrated for testing. It is also called non-incremental testing.

However, there are also risks to using the Big Bang approach. If errors surface during the testing process, the entire system will need a reproach and fix. This will set back the testing process.

Top-down Approach

In the top-down testing approach, testers analyze the main or the top module before moving down to the sub-modules. Thus, the top-level module is designed first, followed by the other modules. After designing and testing the top-level module, the sub-module is merged with the top module.

Bottom-up Approach

In the bottom-up approach, the lower-level modules get preference in contrast to the top modules in the top-down approach. Here, sub-modules are developed and tested before calling and integrating the top modules. The lower-level modules facilitate the merger with top modules after completing testing.

Hybrid/Mixed Approach

A hybrid/mixed approach combines the advantage of Top-down and Bottom-up. This approach has no sequential preference, and you can start testing either from the top or the bottom modules. So, you can test at any point in time, provided the modules are fully ready for analysis.

Point to Note: Top-down and Bottom-up approaches both come under Incremental testing as they follow a hierarchy or sequence for integrating and testing modules.

How to Perform Integration Testing?

Integration testing follows these simple steps:

  • Test Plan: Create a test plan

  • Create Test Cases and Scenarios: Design your test cases and scenarios, followed by use cases and scripts.

  • Execute the Test Steps: Run your tests after the module integrations

  • Identify the Issues: Detect, report, and fix errors.

  • Perform Regression Testing: After all bugs are fixed, perform regression testing.

  • Repeat: Perform the process until there are no more errors or bugs

What are the Similarities Between System Testing and Integration Testing?

Upon careful consideration of System testing vs Integration testing, you will understand that there exist several similarities between the two. Let’s look at all the features that make System and Integration testing similar:

  • System testing and Integration testing leverage Agile methodology that follows regular release cycles. Here, different teams share their testing duties while ensuring stakeholders actively participate in the process. Communication is transparent and well-maintained while considering customers’ opinions.

  • Both types happen in the test environment that simulates the actual conditions of users.

  • System testing and Integration testing cover the functional features of software under testing.

  • They both use the black box testing technique.

  • They both help to analyze system performance and usability.

System Testing vs Integration Testing: Key Differences


System TestingIntegration Testing
Software applications or individual modules are tested end-to-end for their functionsIndividual modules are tested only after integration
Black box testingWhite box and black box testing or grey box testing
Checks that the entire build works successfullyChecks how units work together
Both developers and QA can do itMostly QA conducts the tests
Checks functional and non-functional aspectsChecks only functional features
Comes after Integration testingComes after Unit testing

Wrapping Up

In this article, we discussed how essential System and Integration testing are in the SDLC process. Although both have pros and cons, you need to follow these quality checks to ensure that your system is functioning as intended with all its modules intact.

It is best if you go sequentially and follow the agile methodology to perform both of these tests. This will help you to proceed in the right direction with the right information to test your software application.

By highlighting their differences and similarities, your team can conclude when and how to perform these tests that offer the best results.

Suppose you are looking to move ahead with automation to build your QA team and ease their testing process. In that case, you can go for various automation tools, such as Selenium, Testsigma, Protractor, and Rational Integration Tester. All of these tools provide a bunch of features to carry out the system and integration testing.

We recommend you try a demo of Testsigma and see if the product matches your expectations. But if you are sure about going for a codeless testing automation platform, Testsigma is the no-brainer choice.

Frequently Asked Questions

What comes first in System Testing vs Integration Testing?

Integration testing comes before System testing. Once all the modules’ development and integration are complete, Integration testing checks for compatibility and comprehensibility issues. Subsequently, the application undergoes System testing.

What is an example of System Testing?

A good System testing example would be to check if different user inputs can create the desired output across the applications. For instance, checking an e-commerce website and all its functions is a good System testing example. The website must act as per user and function requirements from end to end.

What are Integration testing examples in real life?

One example of Integration testing would be checking the interaction and data flow between the payment gateway and the shopping cart. Even the flow of control between login, sign-up, homepage, and payment gateway comes under Integration testing examples.

Which tools are useful for System Testing?

Some popular System testing tools are Selenium, HPE Unified Functional Testing (UFT), Robot framework, Testsigma, JMeter, and Galen framework.

What tools are good for Integration Testing?

Some Integration testing tools are Selenium, Citrus, Pytest, Rational Functional Tester, Mockito, FitNesse, Testsigma, and LDRA.


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