Smoke Testing vs. Regression Testing

The term software testing is not a single entity rather it encompasses numerous testing methodologies and techniques for each different level and purpose. Smoke testing and regression testing are two of the most important testing techniques performed over software builds where smoke tests are used to evaluate the stability of the initial or newly developed software builds and regression tests have the task to verify and validate the veracity of the existing functionalities of the application after each modification or on the addition of new feature(s). They both are necessary for the healthy functioning of the build product.

Differences between these two testing are quite clear, still people often gets confused between these two interchangeable terms. Here, we are going to list out some of the notable key points of differences to distinguish between these two methodologies in a very crystal clear manner, but before that let's have a small overview of smoke testing and regression testing.

smoke vs regression testing

Smoke testing

Smoke testing is one of the earliest testing techniques performed over initial or newly developed software builds to evaluate their stability based on the compliance of basic functionalities and features to face-off further more rigorous and thorough testing activities. If a builds fails to pass the smoke test, it is considered unstable and gets rejected instantaneously for further testing whereas on passing the test, the builds is readily accepted for further testing process. This saves the time and efforts of testers and QA team to work on defective builds.

Regression testing

Regression testing may be seen as a type of maintenance work carried out during software testing to ensure that existing core functionalities are not impacted or affected after each modification or changes introduced in the software application. These changes may include patches, modification in code, any addition or deletion in code during bug-fixation process, addition of any new functionalities or features. In simple words, regression testing ensures that a new change does not affect the older and existing functioning of the software application.


Smoke Testing

Regression Testing

1. A surface level testing to evaluate the stability of the software build to undergo through more rigorous and detail testing process. Regression testing may not be considered as a surface level testing but is being used to ensure veracity of the existing functionalities and features of a software application on any new change.
2. Smoke testing may be seen as general health check-up of a software build. It is performed to ensure no side-effects of changes introduced in the software application.
3. One of the earliest & preliminary testing methodologies in the software testing life cycle (STLC). Regression testing is carried out throughout the software testing life cycle.
4. Smoke testing touches and covers all the basic functionalities and features but without getting into depth. It considers the evaluation of all sorts of functionalities and features in detail.
5. Quick and speedy testing technique. Requires considerable amount of time and resources.
6. Smoke tests are executed to either accept or reject build for further testing. Regression testing is not accountable for accepting or rejecting builds for further testing procedures.
7. Also known by the name of build verification test (BVT). No other name.
8. Smoke tests may be executed either by the developers or by the testers. Regression tests are always executed by professional testers.
9. It may be carried out using both manual and automation approach. It may be executed either manually or with the help of automation tools.
10. Smoke testing is followed by the regression testing. Regression testing is carried out frequently throughout the testing phase.
11. No major impact on software project cost due to lesser need of human resources and time. Requires a large amount of time and manpower, and thus significantly affects the project cost.