What is Smoke Testing?


Smoke testing, also called build verification testing or build acceptance testing, is a non-exhaustive software analysis that ascertains that the most crucial functions of a program work but does not delve into finer details.

Smoke testing is the preliminary check of the software after a build and before a release. This type of testing finds basic and critical issues in an application before critical testing is implemented.

The term smoke testing originates from a similarly basic type of hardware testing in which a device passes the test if it doesn’t catch fire the first time it turns on. Daily build and smoke tests are among industry best practices advocated by the Institute of Electrical and Electronics Engineers in Code Complete by former IEEE editor-in-chief and software engineer expert Steve McConnell.

Read more: What is System Testing? Definition & Different Types

When do we do smoke testing?

Smoke testing is performed whenever new software functionalities are developed and integrated with existing builds deployed in QA/staging environments. It ensures that all critical functionalities are working correctly or not.

The development team deploys the build in QA using this testing method. Subsets of test cases are selected, and testers run the test cases on the build. The application is tested by the QA team against the critical functionalities. These series of test cases are designed to expose errors that are in build. If these tests pass, the QA team moves on to Functional Testing.

Any failure indicates that the system must be returned to the development team. We perform Smoke Test whenever there is a change in the build to ensure stability.

Example: A new registration button is added to the login window, and the build is updated with the new code. On a new build, we perform smoke test.

The smoke tests qualify the construction for more formal testing. The primary goal of smoke test is to detect major problems early on. Smoke tests are intended to demonstrate system stability and compliance. A build contains all the data files, libraries, reusable modules, and engineered components needed to implement one or more product functions.

What if we don’t conduct smoke testing?

If we do not perform this testing early on, defects may be discovered later on, which can be costly. Defects found later in the process can be show stoppers, affecting the release of deliverables.

Who will do Smoke Testing

Smoke testing is performed by QA engineers/QA leads after the build has been released to the QA environment. Whenever a new build is released, the QA team determines the major functionality of the application to perform this testing. The QA team looks for show-stoppers in the application that is being tested.

Sanity testing is done in a development environment on the code to ensure the correctness of the application before releasing the build to QA. Typically, it is narrow and deep testing. It is a process that ensures the application under development meets its fundamental functional requirements.

Sanity testing determines the development phase’s completion and whether or not to pass the software product to the next testing phase.

Why do we conduct smoke tests?

Smoke testing is important in software development because it ensures the system’s correctness in the early stages. This allows us to reduce test effort. As a result, smoke tests restore the system to its original state. Only after we have completed smoke testing will we begin functional testing.

  • Smoke test will identify all the show stoppers in the build.
  • After the build has been released to QA, smoke test is performed. Smoke test discovers most defects during the early stages of software development.
  • Smoke test simplifies the detection and correction of major flaws.
  • The QA team can use smoke test to identify defects in application functionality that the new code may have introduced.
  • Smoke test identifies the most serious flaws.

Example 1: Logging window: Clicking the submit button allows you to proceed to the next window with a valid username and password.

Example 2: A user is unable to sign out of a website.

How to Perform Smoke Testing

Smoke testing is typically performed manually, but it is possible to automate the process. It may differ from one organization to the next.

Manual Smoke testing

Generally, smoke testing is done by hand. The approaches differ from one organization to the next. Smoke test ensures that critical path navigation is as expected and does not interfere with functionality. Once the build is released to QA, high-priority functionality test cases must be taken and tested to identify critical system defects. If the test passes, we will move on to functional testing. If the test fails, the build is rejected and returned to the development team for improvement. QA begins smoke test again with a new build version. Smoke test on new builds will be integrated with older builds to ensure the system’s correctness. Before performing smoke test, the QA team should ensure that the correct build versions are used.

Automation smoke testing

Regression testing is carried out using automation. We can, however, use a set of automated test cases to run against Smoke Test. Developers can use automation tests to check builds immediately whenever a new build is ready for deployment.

Instead of manually repeating tests whenever a new software build is deployed, recorded smoke test cases are run against the build. It checks to see if the major functionalities are still operational. They can immediately correct the build if the test fails and redeploy it. This allows us to save time while ensuring a high-quality QA environment build.

All manual steps performed in the software build are recorded using an automated tool by the test engineer.

The cycle of smoke testing

The flow chart below depicts how Smoke Testing is carried out. Once the build has been deployed in QA and the smoke tests have been passed, we will move on to functional testing. We stop testing if the smoke test fails until the build issue is resolved.


Here are a few benefits of Smoke Testing.

  • Testing is simple to carry out.
  • Defects will be discovered early on.
  • Enhances the system’s quality
  • Reduces the risk
  • Progress is easier to access.
  • Saves test effort and time.
  • Easy to detect critical errors and correction of errors.
  • It runs quickly
  • Minimises integration risks

Regression testing vs. smoke testing

Regression testing is a distinct method of ensuring good software code. Regression testing ensures that changes to a program do not introduce new bugs that may jeopardize the software’s performance or integrity. Regression tests, like smoke tests, should be run frequently with each new build. Regression tests, on the other hand, are thorough and detailed.

Regression tests focus on specific software operations and can take several hours to complete. Regression testing, for example, explicitly checks each link on an updated webpage to ensure that each link works as intended. Some regression testing use cases can be automated, such as confirming that adding an item to a cart works or that users can still navigate to their cart and pay.

Smoke testing and sanity testing

The terms smoke test and sanity testing are frequently used interchangeably in the software industry. Some professionals refer to sanity testing as an equivalent to smoke test, while others refer to it as a subset of regression testing. When the term sanity testing refers to a subset of regression testing, the scope of testing is frequently assumed to be narrow and extensive.


Smoke testing should be performed on every build without fail in software engineering because it aids in the early detection of defects. The final step before the software build enters the system stage is smoke test. Each build that is ready for testing must undergo smoke test. This applies to new development as well as major and minor system releases.

Before performing smoke test, the QA team must ensure that the application under test is in the correct build version. It is a simple process that takes little time to test the application’s stability.

Smoke tests can reduce test effort while improving application quality. Smoke testing can be performed manually or automatically, depending on the client and the organization.