Regression Testing vs Integration Testing: Key Differences

You know about regression and integration testing independently, but do you know the difference between them? One re-executes the tests for existing functionalities of the application, while the other checks the connection between various components of the application. Let’s see what does what. We highlight the differences in integration and regression testing in this blog with a table and a few examples. We also discuss the use of automation tools and when and how to use them for regression testing vs integration testing.

So, let’s begin!

What is Regression Testing vs What is Integration Testing?

Before we show the differences between these two testing types, let’s explore their definition and a couple of examples to understand them better.

Regression Testing

Regression testing is a type of testing that involves re-checking software or an application after new changes are introduced in it. This testing process runs functional and non-functional checks on the existing features of the software to ensure that no issues arise due to new code changes. The goal of regression testing is to identify any defects in the present system that may occur due to updates/changes. Regression testing can either be white box testing or black box testing.

You can re-use the test cases in regression testing to verify the existing functionalities. This includes running the same test cases and scripts to get the same output that validates the present features.

An example of regression testing is checking the Camera, Phone, and other applications in your mobile after a system update. Smartphones often receive regular system updates that can hamper the ongoing functions of the phone. Regression testing would assess if any OS or parts upgrade impacted your phone.

Integration Testing

Integration testing checks the communication and data flow between two modules of the same system after integrating them. Let’s look at how this works.

A software consists of several small modules that carry certain features and come together to build the system. Sometimes even when these modules pass the quality test independently, they might encounter data flow issues upon integration. Integration testing verifies the compatibility between these individual parts and ensures they work in unison without any issues after integration. It can be a black-box testing or white-box testing technique.

An example of integration testing would be checking the logical connection between the ‘Proceed to Payment’ page and the payment gateway for an e-commerce application.

When to Use Integration Testing vs When to Use Regression Testing?

Integration testing is run when existing modules connect with new ones or if any new modules are developed, and they integrate. This process checks the quality of the connection between the modules and the flow of data between them.

Regression testing does an overall testing of the previously existing and stable features after functional testing of new features is over. The idea is to ensure that the new changes did not impact the already working ones. Testers also perform regression testing after user acceptance testing (UAT).

When to Automate Integration Testing vs When to Automate Regression Testing?

If these new code builds are frequent, it is better to automate the testing for accurate and quick results.

Many reasons exist to automate your integration and regression testing. For example, if you are running the same test cases repeatedly for regression testing, automating them would make sense as it would save time, cost, and manual effort. This approach frees you up to focus on other work and tests specific parts of the application with high accuracy.

Read more about automated regression testing

In the case of integration testing, automating the test cases is the right choice when you need to check the connection between the two modules logically. You can also opt for automation when the tests are complex and require repeated execution. Proper use of test data and test scripts will allow you to receive the right results and verify communication between the modules. Further, you can go for automation testing if you have to run parallel tests, and doing so manually would occupy a big deal of your time.

Regression vs Integration Testing – Differences

Here are the most common differences between regression and integration testing:

Regression Testing	Integration Testing
It checks the existing and stable functionalities of the application, after a new change has been introduced.	It verifies the modules and data flow between them without focusing on their individual behavior.
It is re-testing the existing features of the application.	It does not re-test the application.
Regression testing comes after functional and UAT testing or any other time when the software undergoes any changes.	Integration testing comes after unit testing.
It only runs and verifies previously executed tests.	This testing adds new tests to check proper data flow between modules.

Automated Regression Testing Tools

Let’s discuss a few tools to run automated regression testing.

Testsigma

A no-code, cloud-based, AI-powered, open-source tool, Testsigma supports all your regression testing efforts by automating the test cases to run the regression. The tool is intelligent and suggests affected areas and relevant test cases after a feature enhancement/release or a bug fix. And you can use Testsigma to run regression testing in sprints that match your organization’s release cycle.Suppose you make a minor change in the application’s UI. Testsigma will automatically catch this alteration and find the test cases associated with this UI change. Other features of Testsigma that make it a perfect regression testing tool are:

• Prioritize test cases to run faster regression testing.
• You can select the test case type (Unit Test, Integration, Functional, Non-Functional, User Experience).
• Run parallel tests to reduce the feedback loop.
• Schedule automated tests to minimize manual intervention and easily detect regressions in code modules.
• Receive insightful and actionable feedback reports to understand the outcome and effectively work on bug resolution.
• It is a no-code tool.

Watir

Watir is an open-source Ruby library for automating web testing. It works on Selenium’s Ruby language bindings, which makes it easy for you to design and write Selenium test cases easily and efficiently. Watir tests the web application the same way as how humans explore it; the framework does that by clicking links, filling out forms, validating texts, checking dropdown menus, and more.

If you make any code changes in the web application, you can use Watir to check the functionality. The tool takes a human approach by running the tests in such a manner that it feels like a human using it, which provides a realistic insight into its working and issues.

Some features of Watir are:

• Makes it easy to write and run Selenium tests.
• Watir installation is supported by Internet Explorer, Firefox, Chrome, Safari, and Edge.
• It can take screenshots and locate web elements using several attributes.
• You can check page performance using Watir.
• Page Objects offer the ability to reuse the code and automate your application.
• Consists of easy-to-use APIs to check popup alerts in your UI or website.

TestingWhiz

TestingWhiz is a codeless platform using which you can test web and mobile applications. It supports end-to-end testing, record and playback testing, cross-browser testing, and more. With already available test cases, you can run automated tests using TestingWhiz to check if any changes in the code, UI, or otherwise have impacted the existing functions.

For instance, if you upgrade the application version with new features in the sign page for new users to register, you can apply this tool to test if the existing login and sign-up functionalities are working along with the newly added one.

Features of TestingWhiz include:

• Run and re-run test cases for testing and regression.
• Schedule automated tests for future runs.
• Codeless automation tool.

Automated Integration Testing Tools

Let’s discuss a few tools to run automated integration testing.

Testsigma

Testsigma is a tool that can easily automate integration testing as it supports web, mobile, desktop and API testing. And it is a no-code platform that makes it simple for testers to write code and run them as and when necessary.

Some features of Testsigma that make integration testing effortless are:

• Create test cases, set up test environments, run tests, analyze results, and generate reports.
• Integrate with bug-tracking systems to quickly and timely track and address the issues.
• Efficiently collaborate with other team members and other teams.
• Customize your test cases to scale them if required.

Tessy

Tessy is an automation testing tool that automates the complete unit test cycle, including integration testing. It mainly performs automated dynamic module/unit and integration testing of embedded software and also determines the code coverage. The tool can automate several functions of integration testing, including importing requirements and comprehensive report generation.Its features include:

• Managing unit test workflow right from the setup of the project.
• After importing the requirements and creating a scenario, Tessy handles the test execution.
• Makes change management easier.
• Allows engineers to test the component variable’s internal values variables and the interfaces between different modules.

Spock

It is a Java-based testing framework. It also leverages Groovy’s features to stay a relevant alternative to JUnit. A test in Spock is called a Specification.

Some features of Spock are:

• Specifications are designed for easy read and write options.
• Offers built-in support for testing concurrent and asynchronous code.
• Consists of an effective mocking and stubbing framework that helps create detailed and efficient test cases for integration testing.
• Spock uses Behavior-Driven Development (BDD) and supports data-driven testing.
• It provides hooks that allow you to set up and tear down resources before and after each test. This can be useful in integration testing to establish connections to databases, external services, or other resources required for testing.

Summary

Regression testing and integration testing are two distinct types of testing that carry different levels of importance in SDLC. They verify two completely different things in an application; the former re-checks the existing functions when new changes are introduced in the software, and the latter checks the connection between modules of the software. In this blog, we bring out the details of the differences between integration and regression testing. We also highlighted the benefits, tools, and a few examples to give you a better understanding of both testing types.

Frequently Asked Questions

Is integration testing part of regression testing?

No, integration testing is not a part of regression testing. They are two different types of tests that check separate functionalities of the application. Integration testing validates the flow of data between the modules, whereas regression testing sees if new changes impact the existing features. However, integration tests can become a part of regression tests once the integration testing is done and passed successfully.

Is regression testing manual or automated?

Regression testing can be both manual and automated. You can reuse the test cases either manually or automate them. Typically, going for automation would be the right choice as it will save you time and effort in re-running the tests.

What is integration testing in STLC?

Integration testing in STLC is verifying the logical connection between individual modules when they integrate to become one system/part of a bigger system. This testing aims to highlight and detect bugs that might be present in the interaction between the modules.