Are There Differences Between Retesting and Regression Testing?

Retesting and regression testing sound alike, and they often need clarification. The main difference is regression testing is for bugs you do not expect, and retesting is for bugs you do. While both retesting and regression testing are vital components of the software testing life cycle, these testing procedures are very different in terms of how, when, and why each kind of test is performed. 

We’ve compiled the top FAQs on everything retesting and regression testing, including benefits, challenges, and why both are crucial for your testing strategy.

What is retesting?

Retesting assesses known bugs and whether they are fixed. Once the bugs are found, developers fix them and then send the app back to the testing environment for verification that the problem has been solved. Retesting is a manual process to confirm functionality is restored after a fix.

What is the purpose of retesting?

Retesting is very important to delivering a high-quality, bug-free, error-free release. First, because retesting tests a fundamental component for quality and functionality, re-testing ensures an original fault is corrected. At the end of a successful retesting process, the bug is closed. Retesting helps to improve the overall quality of an app. 

Retesting also typically takes less time for verification, as it tests only one feature or issue. This is good news for devs, as testing often becomes the main bottleneck. Retesting is performed with the same data and environment, meaning a new testing environment is not required. In retesting, only the build must be new to verify the defect.

What are the challenges of retesting?

Retesting is critical but does not come without unique challenges. As a manual process, retesting requires the knowledge and oversight of DevOps, making retesting time-consuming and laborious. Additionally, there are times when resolving a bug only requires a  minor code change. However, in retesting to solve that single bug, the developer must deploy the code, which can burn time

Retesting can also prove slow-going and frustrating for testers as well. To properly retest, the exact steps must be performed every time to ensure resolution.

What is regression testing?

Regression testing is a software testing process designed to ensure application functions as expected after any new updates, code changes, or improvements have been made. Regression testing checks for unknown issues because of code changes.

What is the purpose of regression testing?

Regression testing offers benefits to DevOps teams, including the ability to automate regression tests. By automating the regression testing process, devs can receive feedback faster and make fixes more timely. This speeds up the testing life cycle and development life cycle - that speed is great news for engineering teams. 

Because regression testing uncovers new bugs or flaws earlier in the software development life cycle, this helps to prevent minor issues from becoming significant issues down the line. With regression testing, problems are identified sooner, which cuts down the labor, costs, and maintenance of resolving a defect (or multiple defects) later in development. In this way, regression testing acts as a safeguard from a minor issue flaring into a significant mess. 

For teams with complex projects requiring frequent modifications and changes, regression testing continually checks quality to protect the app.

What are the challenges of regression testing?

A big challenge with regression testing is the labor and cost associated with this kind of software testing. When performed manually, regression tests take up a lot of developer time, and energy testing features that have already been tested before.  

Another challenge of regression testing is that it can suck up a lot of time. Running after every code change or update, regression testing can bring progress to a screeching halt for large, complex test suites. Additionally, even if regression testing is fully automated, running an entire test suite, or enduring the constant changes of a test suite can also undermine developer progress.

Regression testing can drag down developer experience and drive up machine time. Since regression testing involves running the same tests repeatedly, teams might find it boring, tedious, or low-level. Another issue, in that same vein, is that because manual regression testing can become quite monotonous, it's much easier for DevOps teams to miss or misinterpret test results. 

What are the differences between retesting and regression testing?

There are many differences between retesting and regression testing including the when, why, and how each test is performed. 

When do you retest vs. when do you perform regression tests? 

Retesting is performed before regression testing because retesting makes sure the detected bug is fixed, while regression testing checks the app for defects found after a code change. Retesting is used only for failed test cases, while regression testing is only used for passed test cases. 

Why do you perform retesting vs. why do you perform regression testing?

Retesting only tests for a specific bug and then seeing if that bug has been resolved. Meanwhile, regression testing determines if a new code change or improvement has negatively impacted existing features or created new, hidden bugs.

Another way to think of it is that retesting is for defect verification and regression testing is for unintended side effects after new code changes.

How is retesting performed vs. how is regression testing performed?

Retesting is always a manual process, as it relies on human expertise. Regression testing can also be manual but speeds up immensely through automation. For developers, speedier regression testing is key to better productivity, better developer experience, and faster releases that delight end users and clients alike. 

Can you automate test selection for better regression testing and less retesting?

Automating your test selection reduces the need for retesting and intelligently speeds up your testing suite, including your regression testing. Launchable’s Predictive Test Selection dynamically reorders your tests and identifies the best tests to run based on code changes, your git commit metadata, and the tests that are most likely to fail. 

By automatically selecting the most important regression tests for your team to run, Predictive Test Selection can help reduce the size of your test suit and your testing cycle times. With Launchable, regression testing can become a speedier, wildly more pleasant experience.