Functional Testing Vs Integration Testing - Key Differences

Functional Testing Vs Integration Testing – Key Differences

When a software is in the testing phase, different types of testing techniques and methodologies are followed on different layers. Two such types of testing are functional testing and integration testing. Both play a significant role in ensuring the quality of the product and delivering a top-notch product. In this article, we will discuss functional and integration testing – when to perform them, the benefits of executing these tests, and then the key differences between them.

What is Functional Testing?

Functional testing helps verify that the software works as expected and meets user’s expectations. It is a type of black-box testing that involves testing various aspects of the application, such as user interfaces, APIs, databases, and other system components, to validate that they are working as expected. It doesn’t involve looking into the internal working of software functions – just observing output on the appropriate input.

Functional Testing Example

Let’s consider you are testing a website that has a login feature. The functional requirement is that users should be able to log in to the website using their username and password.

To verify if the login functionality is working as expected, follow the below test steps,

  1. Open the website on a browser
  2. Navigate to the login page.
  3. Enter a valid username and password and click the login button.
  4. Verify that the user is logged in and redirected to the home page.

These steps will ensure that the website’s login feature is working correctly and meets the requirements.

Advantages of Functional Testing

Some advantages of functional testing are mentioned below:

  • Ensures specified requirements are fulfilled: Functional testing ensures that software provides all the required functionality as expected.
  • Early bug detection: Functional testing helps you to save money and cost by finding bugs in the early stage of the software development life cycle.
  • Richer user experience: By testing all the functionality is working as expected, functional testing helps you to provide a rich user experience.
  • Saves time to ship the product: By catching a bug in the early stage of the software development life cycle, it saves time to ship the product.
  • Improve the overall quality of the product: From ensuring the project requirements to saving development time, it improves the overall quality of the product.

When to perform functional testing?

Functional testing is ideal for performing when all the software functionalities related to a feature have been developed.

Functional testing is typically performed before integration testing and is executed before releasing the software product into the market.

What is Integration Testing?

Integration testing is when two or more components are integrated and tested as a whole. It ensures that smaller components are working correctly together after integration and provides an error-free user interface for the end users. It helps to improve the performance and scalability of the software and increase the overall software quality.

Integration Testing Example

Check that the interface between the “Add to cart” and “My cart” modules on the e-commerce application is working as expected and that the user is able to add products to the bag.

Follow the below test steps to check this scenario,

  • Try to add one or more products to your shopping cart.
  • Check that the products are successfully added to the cart and are available in the cart.
  • If products are added to the cart, the user must be able to check out next.

Advantages of Integration Testing

  • Early bug detection: Integration testing helps you to test two or more integrated components as a whole and ensure they are working properly together.
  • Easy to debug: Integration testing deals with the individual integrated module, which makes it easy to debug and find a minor bug too.
  • Improved test coverage: It ensures that all the software modules are tested together, resulting in improved test coverage and a more comprehensive testing approach.
  • Improve the performance and scalability: It helps to optimize the individual software module and its performance and scalability.
  • Increase the overall software quality: Integration testing increases the software’s quality by detecting the bugs early, providing better test coverage, and optimizing for scalability.

When to perform integration testing?

Integration testing is performed after unit testing and functional testing in the software development process. Integration testing should be performed after the individual components or modules of a software application have been unit tested and are ready to be integrated. It is designed to test the interaction and communication between different modules of a software application.

Comparison – Functional Testing Vs Integration Testing

The table below depicts the integration test vs functional test core differences,

Functional TestingIntegration Testing
Helps verify that the software is functioning as expected and meets the user’s requirementsHelps test how different software modules interact with each other
Executed by testersExecuted by testers and developers
Helps identify issues that might interrupt the application’s workingHelps identify issues that might occur while integrating different components
It is performed before integration testingIt is performed before integration testing

When to automate your functional and integration testing?

You should automate the functional and integration testing if you repeatedly execute the same functional and integration tests, and you see an ROI on automating them. Automated testing, when planned and executed well, reduces the total time and effort required to perform testing, thus accelerating the time to market, and also provides an ROI.

Testsigma is a powerful test automation tool that lets you automate web, mobile, and desktop applications in the same place. It is an AI-driven platform that lets you create test cases in plain English, which makes the testing 5x faster.

Functioanl Testing vs Integration Testing

The following are some of the top benefits offered by Testsigma,

  • It is a no-code test automation tool that lets you author simple and complex tests in simple English
  • It is very simple and easy to use
  • Also comes with a record and play feature to record user actions and later automate them as test cases on the cloud.
  • Automate cross-browser testing across 3000+ real devices and 1000+ browser/OS combos.
  • A no-code test automation tool that does not require coding to write test scripts
  • Automate your web, mobile, desktop, and API tests in one place
  • Easy test maintenance on the cloud
  • No need to download any tools or frameworks
  • Supports parallel test execution

Testsigma is also available as an open source and free version.Start automating your functional and integration tests with Testsigma Open Source

Wrapping up

Functional testing and integration testing are closely related to each other, but they are not the same. We hope that this article helped you understand them and their differences better.

Frequently Asked Questions

Is functional testing manual or automation?

Functional testing can be both manual and automated. Manual functional testing involves human testers executing test cases manually to verify the software’s functionality. On the other hand, automated functional testing involves using automation testing tools to execute test cases and compare actual results with expected results. Automated functional testing is typically faster, more efficient, and repeatable than manual testing.

Is integration testing the same as UAT?

No, integration testing is not the same as user acceptance testing (UAT). They both serve different purposes in the SDLC. Integration testing is focused on verifying the interactions between different modules of the application, while UAT is focused on validating the software from the perspective of end-users.

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