To secure your deployments and prevent each update from becoming a source of errors, it is crucial to incorporate automated testing strategies. Non-regression testing (NRT) is the essential safeguard for ensuring the stability of your product.
What is a non-regression test (NRT)?
A regression occurs when a code change (bug fix, update, or new feature) unintentionally affects parts of the application that were already stable. The non-regression testing (NRT), also known as regression testing, involves verifying that these changes have not altered the behavior of existing features. In short, it ensures that what worked yesterday still works today.
What are the different types of non-regression tests?
Depending on your resources and goals, there are several approaches you can take:
- TNR Fix: We reuse existing tests without making any major changes.
- Full TNR: A comprehensive “retest” of all product components from the beginning.
- Selective TNR: We target only the parts of the code that may be affected by the changes.
- Gradual TNR: New scenarios are created as the product's characteristics change.
- Partial TNR: Performed specifically when merging different code modules.
- Unit-by-Unit TNR: Testing the code in isolation, component by component.
Why run non-regression tests?
The main challenge is ensuring software quality.
- User Experience: A stable product strengthens your brand image and builds customer trust.
- Revenue Protection: Preventing critical bugs (payment failures, broken checkout processes) helps avoid direct financial losses.
- Cost-effectiveness: It is much less expensive to fix a bug during the testing phase than after the software has gone into production.
- Security: TNRs can detectpotential vulnerabilities introduced by new lines of code.
When should you carry out your TNR campaigns?
We recommend incorporating TNRs as early as possible in the product lifecycle. They are essential during:
- Fixing bugs.
- The addition of a new feature.
- Modifying an existing feature.
- An update to the environment (data, servers).
- Source code optimization (refactoring).
What are the differences between functional validation and non-regression testing?
These two concepts are often confused, yet their objectives and processes differ.
On the one hand, the validation functional test aims to determine whether a new feature meets the initial requirements. It uses new test scenarios, often initially executed manually to test positive and negative cases.
On the other hand, non-regression testing aims to verify that existing systems have not experienced any code breaks. Here, we use test cases that are already known and stable. This is why non-regression testing is the ideal candidate for automation, unlike validation testing, which often requires human intervention during its first run.
Focus: What Is a Graphical Non-Regression Test?
Also known as visual comparison test, it ensures that the user interface (UI) remains identical down to the pixel (pixel-perfect) after an update. It verifies the placement, size, and color of elements (buttons, text, images) across different browsers and resolutions, while ensuring that all required legal notices are present.
How do you run non-regression tests?
Regression tests are, by their very nature, time-consuming and repetitive. The use of an automated testing tool is therefore a best practice. Automation enables continuous testing throughout the development cycle (CI/CD), identifying defects immediately before they reach your end users.
Note on Limitations: Despite the power of automation, the QA teams must prioritize the most critical scenarios to meet budget constraints and delivery deadlines.
Tired of regressions after every deployment? Find out how Mr SURICATE your TNRs without writing a single line of code to ensure your updates are secure at all times.
FAQ
What is a non-regression test (NRT)?
This test verifies that a code change (fix, enhancement, update) has not introduced a regression—that is, broken a feature that was previously working. It serves as a safeguard to ensure the reliability of every deployment.
When should you run non-regression tests?
For every significant change—such as a new feature, a bug fix, or a version upgrade—and before every deployment to production. By automating these processes, we can run them with every release without overburdening the teams.
What is the difference between functional testing and non-regression testing?
Functional validation verifies that a new feature works as expected; regression testing verifies that existing features still work after a change. The two are complementary.
Further Reading
To see the solution in action, check out our non-regression tests.
