Introduction
Let’s talk about something that often confuses many people in the QA world- smoke testing, sanity testing, and user acceptance testing (UAT). It’s not unusual to see these terms used interchangeably, but in reality, they serve distinct purposes in the software testing process.
In this article, we’ll break down what each one is, how they differ, and why they’re so important. Whether you’re a newbie to the testing world or just need a refresher, this guide will help clear up the confusion between smoke testing, sanity testing, and UAT.
Since all of them are quick checks, it’s easy to mix them up. Let’s go over the basics and help you understand exactly what each type of testing is all about.
Smoke Testing or tester acceptance testing
Smoke testing is a subset of acceptance testing. It’s usually the first step in the testing process and is executed before any detailed functional or regression tests are done. The idea is simple: verify that the critical functionalities of a deployed software build are stable.
The main goal of smoke testing is to check if the most important features of the system are working as expected. It’s a bit like a “go/no-go” check- if it fails, then there’s no point in moving on to more detailed testing. You’re saving time by catching major issues early on.
Real-world Scenario
Let’s say your team has just deployed an online banking system. A smoke test would confirm that users can log in, view their account balance, and log out. These are the basic functionalities that the system must handle correctly before diving into more thorough testing.
Advantages:
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Early detection of major issues: Catch critical problems early in the process.
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Saves time and resources: If the software fails the smoke test, there’s no need to waste time on detailed testing.
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Minimal integration risk: Focusing on the most important features reduces the chance of deeper integration issues later.
Limitations
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Limited scope: It only tests the most critical paths, so other smaller bugs might go unnoticed.
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May miss edge cases: It’s not detailed enough to catch every issue in the software.
Cost Considerations
Skipping smoke testing can be a costly mistake. If the core features of the system are flawed, the time and resources spent in later testing stages could be wasted, resulting in delays and added costs.
Sanity Testing
Once the software has passed the smoke test, the next step is sanity testing. This is a subset of regression testing, and its main purpose is to ensure that the changes or bug fixes made in the software are functioning as expected. Sanity testing is done after a smoke test to check that recent updates didn’t break the system’s core functionalities..
Real-world Scenario
Imagine you’ve just updated an app with a new feature, such as fingerprint login. Now, after the smoke test, you’d run sanity testing to make sure the new feature works as intended without interfering with existing features, like the password-based login.
Advantages:
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Quickly identifies core issues: It’s fast and easy to spot if something’s not working as expected.
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No need for documentation: Sanity testing doesn’t require a lot of paperwork or test cases.
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Less time spent on regression testing: Focus on specific areas of the system that have changed, saving you time.
Limitations
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Narrow focus: Sanity testing is limited to checking specific changes, so it won’t test edge cases or how the new feature interacts with the rest of the system.
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May miss interactions with other features: Sometimes, issues between new and old features are overlooked.
Cost Considerations
Skipping sanity testing can cause bigger issues down the line. If a feature is broken but goes unnoticed, you could end up with customer dissatisfaction and higher costs for troubleshooting post-launch.
User Acceptance Testing (UAT)
Now, let’s get to the final testing phase: user acceptance testing (UAT). This comes at the very end of the development process and is usually the last phase before the software is released. It’s conducted by actual end-users or the client themselves. The goal of UAT is to verify that the software meets the client’s requirements and works well in real-world scenarios.
Real-world Scenario
For an online grocery shopping platform, UAT would involve real users browsing the site, searching for items, adding them to their cart, and completing the purchase. This ensures that everything works as intended from a user perspective and that the usability is on point.
Advantages:
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Keeps maintenance costs low: Catching issues early means you’ll have fewer bugs to fix post-launch.
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Reduces the risk of defects in production: UAT helps ensure that your software is truly ready for release.
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Increases user satisfaction: When the software meets end-user expectations, customer satisfaction goes up.
Limitations
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Can be time-consuming: UAT often takes longer because it’s conducted by actual users, not testers.
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Depends heavily on user participation: If the users aren’t representative of your target audience or don’t test thoroughly, problems might be missed.
Cost Considerations
Cutting corners in UAT can be incredibly costly. Bugs found in production are not only more expensive to fix, but they can also damage your brand reputation and result in lost revenue.
To simplify it, we outlined the key differences between smoke, sanity, and user acceptance testing in the table below.
| Smoke Testing | Sanity Testing | User Acceptance Testing (UAT) |
| It’s performed to check the critical functionalities of the build | It’s performed to check the new functionalities or bugs that have been fixed | It’s performed at the end to check whether the software meets the customer’s requirements or not |
| It’s performed by developers or testers | Testers perform it | It’s performed by the end user or the client |
| Smoke Testing exercises the entire system from end to end | Sanity Testing exercises only the particular component of the system | UAT exercises the system by using random inputs |
| It’s usually documented and scripted | It’s usually not documented and unscripted | It’s usually documented and scripted |
Conclusion
To sum it up, both sanity testing and smoke testing are quick checks that help you avoid wasting time on testing a broken build. Smoke testing ensures that the critical features are working, while sanity testing verifies that recent changes are functional.
User acceptance testing (UAT), on the other hand, is the final check to ensure that the software meets the client’s requirements and works well for the end-user. These tests might seem similar, but each serves a unique purpose.
In fact, sanity testing and smoke testing are often combined in the industry to speed up testing and make the process more efficient. That’s why the terms can sometimes get confused or used interchangeably.
So, whether you’re running smoke testing, sanity testing, or UAT, it’s all about ensuring the software is stable and ready for release
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