Regression Testing Meaning and Its Types

Any piece of software needs rigorous testing to ensure users won’t experience glitches or latency as they use it. Regression testing is a particular type of software maintenance that ensures that, as software is changed or upgraded, problems don’t suddenly appear due to those changes.

This keeps clients and users happy and ensures software development teams retain a sterling reputation. Knowing how to conduct regression testing properly increases the resilience of web applications and other types of software, as well as the resilience of the company crafting those apps.

What is regression testing?

Regression testing, or black box testing, is one software analysis method designed for the in-life testing of existing apps and software.

Essentially, regression testing (regress–going back, to the previous state of something) is retesting elements of a piece of software that has already been rigorously tested, solely for the purpose of finding out how these elements may have been affected by upgrades, enhancements, bug fixes, or other changes. This includes functional and non-functional tests.

Any modification to the software, including a completely new build, should result in regression testing to ensure all features of the software still function as expected.

It’s important to test software elements that haven’t experienced any direct modifications, as well as elements that have been changed, to ensure that the entire application still functions correctly.

Why is regression testing important?

As software developers and testers, the last thing we want to do is spend a lot of time running unnecessary tests.

Every second is vital, especially when we are working on multiple projects or dealing with clients that require regular changes and updates to their software.

While we want to maximize our time and productivity, it’s these types of clients that actually require the most regression testing on their enterprise software products.

The more modifications a piece of software goes through, the more important regression software testing becomes.

If we decide to work on another project and skip regression testing for this client, we could claim back a few hours of productive time.

However, if the client then encounters a serious problem in a few days because of an error caused by a recent change, it will take us a lot longer to fix the issue, in addition, we will have created genuine business-critical issues for my client.

For example, a client may submit a change request to adjust how amounts are shown within a piece of accounting software.

We could consider implementing this new functionality as a quick fix, make the change, and move on to the next piece of work.

The next day, we might have the client back on the phone wondering why figures are disappearing or not adding up to the right totals within the same piece of accounting software.

At this point, we have to take a deep dive into the issue, try and replicate the problem, and potentially trawl the code to find the trouble.

If we would have taken the time to perform regression test cases, we would have had total confidence that no issues like this could arise — and so would our client.

Challenges of regression testing

The regression testing process isn’t always simple, which is why there are a few different methods for performing this kind of software testing.

Challenges we face when it comes to regression testing include:

• Full knowledge of all the existing features of the software: this can be a challenge when taking new staff on
• Cost: because regression testing takes time, it can become expensive, especially for software that requires regular patches and updates
• Time limitations: smaller teams, in particular, may struggle to find the time to perform thorough regression testing
• Monitoring: it’s essential to make a record of each test performed to ensure no software element is left unchecked
• Conflicts of priorities: businesses may decide that new projects take precedence over testing old ones

Engaging the entire DevOps and quality assurance teams with regression testing helps to overcome some of these challenges, especially when they understand that the cost implications of not performing tests could be severe.

Regression testing methods

Thankfully, it’s rare that any testing team has to perform complete manual testing anymore. Test automation is possible via a range of regression testing tools, such as Selenium or Testsigma.

Developers may also decide to create their own regression test suite of tools using open-source automation servers like Jenkins or Azure DevOps, previously known as TFS.

Codeless or no-code tools can make manually coding test scripts a thing of the past.

A regression test plan is essential to prevent bugs and glitches and also to maximize the DevOps team’s productivity.

In addition to an automated test tool, we need to make sure we have a rigorous testing process in place to avoid regression cycles that continue for days or even weeks.

To do this, it’s essential to fully understand what type of software testing needs to be employed.

The following are the types of regression testing

1. Complete regression testing

The most thorough form of regression testing is to redo all existing test cases for all parts of the software.

This is sometimes called a “Re-Test All” or “Re-Examine All.” This is highly time-consuming and, therefore, costly. However, for multiple change requests or a full upgrade, it could be essential.

2. Selective regression testing

This is a form of test case prioritization that picks out particular aspects of the software to test and ignores the elements deemed unnecessary.

This process usually uses AI or ML (machine learning) to ensure the right test cases are performed.

These may use previous test data or data on software usage and existing errors to determine which test cases are most important to prevent new bugs from developing.

Selected test cases will feed back into the relevant tools to improve the process moving forward.

3. Partial regression testing

This is similar to selective testing, but the selection of test cases tends to be manual rather than automated by AI. Partial testing usually occurs when small amounts of new code are added, and just these elements need to be tested.

There may be occasions when parts of the software that could affect one another all need to be tested. This is known as regional regression testing.

4. Unit regression testing (URT)

This is a method whereby the tester will single out the unit that has been altered and only run testing here.

This method has limitations, as it does not consider the impact that changes on this unit may potentially have on other elements of the software.

However, single-unit testing is sufficient for very small feature change requests or to test units in isolation from their dependencies, for example, when trying to replicate an error that impacts the existing functionality.

5. Progressive regression testing

When the specifications are altered or changed and all new test cases or new scenarios need to be developed, this form of testing is utilized in the software testing process.

By carrying out this type of testing, it is possible to make sure that none of the features from the old, out-of-date version have been compromised in the new, improved version.

6. Corrective regression testing

This is one of the most common types of regression testing and is essentially a re-run of existing, reusable test cases to check for data consistency or to replicate a result.

No code changes have to occur to perform corrective regression testing. Corrective testing may also occur because a change is spotted that wasn’t in the client's specification.

Lastly!

In an agile software development environment or one that utilizes continuous integration (CI), changes and requests for frequent changes are common; therefore, a robust regression testing strategy is even more vital.

Alongside functionality testing and smoke testing, regression testing is critical to ensuring high-quality enterprise software and apps that provide the functionality and flexibility clients require.

Informed regression test selection and test execution ensure continuous performance, even with the most complex test cases.

We make sure providing quality built-in enterprise software and applications from the start-to-end process.

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