Sanity Testing vs Regression Testing: Differences Explained

Testlio

October 29th, 2024

One of the major challenges in software development is ensuring that new changes do not disrupt existing functionalities. This is where testing methodologies like sanity testing and regression testing come into play. However, many teams struggle to understand the differences between these two approaches and when to apply each effectively. 

In this article, we will look into sanity testing vs regression testing, exploring their purposes, scopes, execution timings, and resource requirements. We will also discuss when to apply each method individually and how their combined use can improve overall testing efficiency and software reliability. 

Here’s a quick comparison of sanity testing vs regression testing:

What are the Differences Between Sanity Testing Vs Regression Testing?

Sanity testing and regression testing are essential methodologies in the software testing life cycle. Each serves different purposes and methodologies. 

Here is a detailed comparison of sanity testing vs regression testing:

Scope

Sanity Testing has a narrow focus, concentrating specifically on the application’s functionalities or components that have undergone recent changes. For instance, if a bug is fixed in a specific module, sanity testing will validate that particular module without examining the entire application. 

In contrast, regression testing has a much broader scope. It covers the entire application or system to ensure that new code changes do not negatively affect existing functionalities. For this reason, even features that have not been altered should be tested to ensure they continue to function properly.

Depth of Testing

Sanity testing is typically considered surface-level testing. It involves checking only a limited number of functionalities to confirm their stability after recent changes. This type of testing does not require exhaustive test cases; instead, it focuses on quickly verifying specific areas of concern.

Regression testing, on the other hand, involves a deep and thorough examination of the software. It tests various scenarios, including edge cases, and ensures that all functionalities work as expected after modifications. This depth is crucial because even minor changes can have unforeseen effects on other parts of the application.

Objective

The primary goal of sanity testing is to quickly validate specific functionalities after minor changes or bug fixes. It is an initial check to verify the application is stable enough for further testing. If sanity testing passes, it indicates that the most critical aspects of the software are functioning correctly. 

In contrast, regression testing confirms that recent changes have not introduced any new defects into existing functionalities. Through this testing, previously working features remain functional despite new code additions or modifications. It acts as a safeguard against potential regressions caused by updates.

Execution Timing

Sanity testing is usually executed after smoke testing and before regression testing in the software development lifecycle. It is performed when minor changes are made to validate that those changes work correctly before more extensive tests are conducted. This quick validation helps identify any immediate issues early in the process.

On the other hand, regression testing is conducted after significant changes or updates, such as new features or bug fixes, have been implemented in the software. It ensures that everything functions correctly across the application following these updates.

Frequency

Sanity testing is typically performed less frequently than regression testing and only when minor updates or bug fixes need quick validation. Its focused nature allows it to be executed as needed without requiring extensive planning or resources.

In contrast, regression testing is conducted regularly throughout the development cycle, especially after major releases or updates. It keeps software stable and prevents any new code from disrupting it.

Resource Requirements

Sanity testing generally requires fewer resources compared to regression testing. Because it focuses on specific areas rather than exhaustive coverage, it can often be performed manually and typically takes less time due to its limited scope.

Regression testing demands more resources, including time and manpower, especially when automated testing tools are utilized for extensive coverage. Often, regression tests require careful planning and coordination among team members to make sure they cover all possible scenarios.

Automation Capability

While sanity testing can be performed manually, it may also incorporate automation for efficiency in larger projects. However, due to its focused nature and limited scope, it is often less formalized than regression tests. Automation can help speed up the process but may not be prioritized given its less frequent execution.

In contrast, regression testing is frequently automated due to its repetitive nature and extensive coverage requirements. Test automation speeds up the process of running large test suites and provides faster feedback about functionality after code changes.

When Should You Use Each Testing Method?

 Sanity testing and regression testing play different but complementary roles in this process. It is important to know when to apply each method to increase the efficiency and effectiveness of the testing cycle. 

Here are a few instances when you might want to use each tested method individually as well as in combination.

Sanity Testing

Sanity testing is best used in the following scenarios:

• Post-Bug Fixes: When specific bugs have been fixed, sanity testing ensures that the fixes work correctly and have not broken any related functionality.
• After Minor Changes: When minor changes or enhancements are made to the application, sanity testing quickly verifies that these changes are functioning as expected.
• Initial Build Verification: After receiving a new build, sanity testing can be used to verify that the build is stable enough for more extensive testing.
• Time Constraints: When there is limited time available, sanity testing helps in quickly validating the critical functionalities without going into detailed testing.

Regression Testing

Regression testing is most effective in the following situations:

• Post-Deployment: After deploying new features or updates, regression testing ensures that the existing functionalities are not adversely affected.
• Major Code Changes: When significant changes are made to the codebase, regression testing helps in identifying any unintended side effects.
• Regular Testing Cycles: As part of the regular testing cycle, regression testing ensures that the application remains stable and reliable over time.
• Automated Testing: When using automated testing frameworks, regression testing can be scheduled to run regularly, providing continuous validation of the application.

Using Both Methods

Using both sanity and regression testing together can be highly beneficial:

• Complementary Approaches: Sanity testing can be used to quickly validate specific changes, while regression testing provides comprehensive coverage to ensure overall stability.
• Resource Optimization: By performing sanity testing first, you can quickly identify any major issues before investing time in detailed regression testing.
• Balanced Testing Strategy: A balanced testing strategy that includes both sanity and regression testing helps maintain high-quality standards while effectively managing time and resources.

Conclusion

Sanity testing provides a quick validation of specific functionalities after minor changes or bug fixes, ensuring that recent updates do not disrupt the critical parts of the application.  On the other hand, regression testing involves examining the entire application to ensure that new changes don’t negatively impact existing features.

By strategically applying both sanity and regression testing, development teams can achieve a balanced testing strategy that optimizes resources and maintains high-quality standards. Sanity testing can quickly catch major issues, while regression testing provides the in-depth coverage needed to provide long-term stability.

For comprehensive testing solutions that enhance your software quality, consider partnering with Testlio. Testlio offers expert testing services tailored to your needs, including both sanity and regression testing.

Contact us today to learn more about our services and how we can help you achieve your testing goals.