What is Smoke Testing and Why Is It Important?


Have you ever thought about what goes on behind the scenes of the applications that you download? Before you get a cool new update in your App Store or before a new app is released to the public, a big effort is made in ensuring the stability of the application so that users have the smoothest experience possible.

We know that software has to be designed and written, but that's not all. After designing the interface and writing the perfect code, the software has to be tested. Why? Let's say an app works flawlessly, every functional aspect of it does what it's supposed to do. But what happens if the developers decide to add another button to the drop-down menu? Lines of code are added in the same fashion as the previous buttons for the menu. On paper, this change shouldn't affect the software, as it doesn't break the code since it simply adds another button to the list of buttons. But when you open the app—it crashes. This is where the importance of software testing becomes evident—or smoke testing in particular.

What is smoke testing?

TestDevLab QA engineer performing smoke testing

The term ‘smoke test’ originated in the plumbing industry, where plumbers would channel smoke into the piping system to detect any leaks or cracks and fix them. By doing so, they could confirm that the system worked before it was used by the public.

Smoke testing, often confused with sanity testing, is a type of software testing that is performed to check if the basic functionalities of a software application are working properly. The aim of smoke testing is to identify and address any major issues or defects in the software, and ensure that the application is stable enough for further testing. In smoke testing, the software build is deployed to a quality assurance environment for the testing team to verify the stability of the product/application. Smoke tests confirm that the software product can proceed with further testing and ultimately be released to the public.

In simpler terms, smoke testing is a cheaper and quicker way to ensure that the software’s main functions work properly before it is tested further and uploaded for the public to download.

If the smoke test fails, developers can use the application logs or screenshots uploaded by the tester to locate and fix said issues.

What types of smoke tests are there?

There are three types of smoke tests:

  1. Manual tests. The tester writes and modifies the test cases for the software being tested. Then the tester follows these test cases and manually goes through the application, noting its behavior.
  2. Automated tests. These tests are run automatically using an automation testing tool. This type of smoke testing may be better to use when the project has a tighter deadline.
  3. Hybrid tests. Hybrid smoke testing uses a combination of manual and automated smoke tests to achieve better testing performance and greater test coverage.

Now that you know what smoke testing is and the different types of smoke testing, we can move on to why smoke testing is important and should not be overlooked.

Why is smoke testing important?

There are many benefits of smoke testing. For one, smoke testing helps to identify defects earlier and is cost-effective. If the test passes, the software build can be released to the public sooner, as there are less issues to be found in subsequent testing. Similarly, if the smoke test fails, the issue can be located and fixed quicker, minimizing potential damage before testing it further. This saves time, money, and effort.

Another benefit of smoke testing is that it reduces the risk of failure and is quick to do so. After testing, a progress sheet is filled and bug reports are made. This makes it easier to see which areas of the app are working and makes it easier for developers to pinpoint which exact test step triggered a bug to appear or a crash to occur.

An example of a smoke test summary report
An example of a smoke test summary report

What are the disadvantages of smoke testing?

The main disadvantage of smoke testing is that it can’t cover every functional and non-functional aspect of an application. As previously discussed, smoke testing will check whether the main functions are operating correctly and may assess some areas or functions that are prone to issues, if this has been predefined.

Though smoke testing is quick, for large-scale projects that rely only on manual testing, then the testing process might take longer to execute. This means that more effort may be required from the testing team and the developers, which in turn would make the process more expensive.

Additionally, even if the test passes, it doesn't guarantee a 100% error or bug-free environment. Test cases used in smoke testing usually specify the number of times a function should be tested. For example, let's say the function needs to be tested 10 times. If the function passes the test 10 times, it is considered successful. But what happens if the application crashes on the 11th test? This is why smoke testing cannot guarantee that the application will be completely free of issues and bugs.


While smoke testing is a quick and efficient way to ensure the stability of a software build and identify major defects early on, smoke testing alone cannot uncover all software issues. Instead, it should be used in conjunction with other testing methods to deliver the best app experience to consumers. Nevertheless, smoke testing is an important part of the software testing process and is a great way to streamline testing efforts.

Looking for experienced software testers who can help you to detect any software issues and deliver a high-quality product to users? Contact us with your project details and find out how we can be of service.

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