What is Smoke Testing? A Comprehensive Guide

Among the various types of testing in software QA, smoke testing holds a special position. It is often the first line of defense against bugs and issues, offering early indication whether the software build is stable enough for further testing.

This article takes a deep dive into what smoke testing is, why it’s important, how it’s done, and why your software development process just can’t live without it.

What is Smoke Testing?

Smoke testing is the initial testing phase applied to a software application to check whether the most important functionalities are working properly. The term ‘smoke testing‘ has its roots in the original hardware test of a device, in which a device would pass if it didn’t catch fire (literally produce smoke) on the first power-up.

Smoke testing, regarding software development, is a kind of software testing that consists of determining whether the build is sufficiently stable to justify further testing. Sometimes this is also called ‘build verification testing‘ or ‘confidence testing.’ Smoke testing focuses less on exhaustive testing but covers major functionalities working as expected.

Key Features of Smoke Testing

• Preliminary Testing: Smoke testing is the initial step before any comprehensive testing. It checks the basic functionality to ensure that the software build is stable.
• Focused Scope: Unlike regression testing or system testing, smoke testing focuses on the most critical areas of the application. It doesn’t delve into the details but ensures that the essential features are operational.
• Automation-Friendly: Smoke tests are often automated because they are repetitive and need to be executed whenever a new build is available.
• Quick Feedback: It provides quick feedback on the stability of the software build, helping the development team address major issues early in the process.

Key Characteristics of Smoke Testing:

• Preliminary Testing: Smoke testing is done at the very beginning before any detailed testing. It tests for basic functionality, which gives proof that the software build is stable.
• Narrow Focus: Smoke testing, unlike regression testing or system testing, focuses on the most critical areas of the application. It will not delve into details but ensures that main features are up and running.
• Automation-friendly: Smoke tests are usually automated, as they are repetitive and need to be run each time a new build is available.
• Quick Feedback: It gives quick insights into the stability of the software build so that major issues can be addressed by the development team early in the process.

Smoke testing is highly effective at catching major bugs early, thus reducing the effort needed in subsequent testing phases. By identifying issues early, teams can save up to 30% of their total testing resources​.

The Importance of Smoke Testing in Software Development

Smoke testing is one of the major activities in a software development life cycle. The importance can be understood from several aspects:

1. Early Detection of Critical Issues

Smoke testing is usually done to detect major issues at the initial stages of the development cycle. By focusing on core functionalities, it identifies major defects and bugs before beginning more detailed testing. This early detection prevents the team from wasting time on builds that are too flawed to move further.

2. Saves Time and Resources

Smoke testing saves lots of time and resources by identifying unstable builds early in the process. Doing detailed testing on a build that fundamentally doesn’t work would waste effort. Thus smoke testing ensures that only stable builds proceed to the next stages of testing.

3. Boosts Confidence

Smoke testing provides both developers and testers with confidence, knowing that the build is at least minimally functional. This confidence is important for maintaining development momentum. A failed smoke test means the development team must revisit the build, while a passed test gives the green light for more rigorous testing.

4. Enhances Collaboration Between Teams

Smoke testing encourages collaboration between development and testing teams. Since it is performed right after a new build is delivered, it creates a touchpoint where both teams can discuss the build’s stability and decide on the next steps. This keeps everyone aligned on the quality and readiness of the build.

Different types of smoke testing?

Smoke testing is the preliminary level of software testing aimed at identifying basic failures before a build is sent for more thorough testing. Several types of smoke testing in general are practiced as follows:

1. Manual Smoke Testing: Basic tests are performed by the testers to see if major functionalities work as they should. It usually applies to smaller projects, or for projects where automation would be impractical and ineffective.
2. Automated Smoke Testing: Scripts automatically execute tests on new builds for up-to-the-minute tests; best for continuous integration and delivery environments.
3. Build Verification Testing (BVT): This automated test, also referred to as Build Acceptance Testing, verifies every new build that it is testable before the build proceeds on to other, more detailed testing phases.
4. Integration Smoke Testing: Ensures that all major components of the system interface correctly with each other, which is important on large projects when different teams are developing the components in parallel.
5. Smoke Testing in Production: This runs test cases on live systems to ensure the deployment in the production environment does not disrupt key functionalities.

How Smoke Testing is Conducted

Performing smoke testing involves a few predefined steps. The intention is to make sure that the process will be systematic and it provides the best way of identifying if the build is stable enough for further testing. This is how smoke testing is usually performed:

1. Selection of Test Cases

The first step is test case selection, which will be executed in smoke testing. The test cases are selected based on the most important functionalities of an application. The underlying concept is to focus on “smoke” or the basic functionalities that have to work if the application has to be considered stable.

2. Preparation of the Test Environment

Next, the test environment should be prepared. This is the setting up of the environment where the smoke tests will be executed. It’s imperative that the environment resembles the production environment as much as possible to guarantee the precision of the test results.

3. Execution of Test Cases

The next steps involve the execution of the test cases, either handled manually or by automation, after the selection of test cases and setup of an environment. Automation is used in many places for smoke testing, as it has to be performed for every new build.

4. Analysis of Test Results

After the test cases’ execution, results are analyzed. If the tests passed, it means the build is stable and can proceed for more detailed testing. In case tests failed, that would mean there exist significant issues that need to be addressed by the development team.

5. Reporting

Finally, smoke test results are documented and reported to the concerned stakeholders. The report usually contains information about the passed or failed test cases and problems encountered during the testing.

When to Perform Smoke Testing

Smoke testing is carried out at various phases of a software development life cycle:

• After New Build: Whenever a new build is created, smoke testing is performed to ensure that the build is stable.
• After Major Updates: This ensures that when huge updates or changes have been made to the code, the core functionality remains unbroken.
• During Integration: Smoke testing ensures the integration of different modules of software hasn’t brought any critical issues in the software.

Advantages of Smoke Testing:

1. Quick Feedback:Provides fast feedback about the stability of a build with which teams can identify critical issues as early as possible.
2. Cost-Effective: It detects major defects in the early moments of the development cycle, thus reducing the overall cost of bug fixing later on.
3. Enhances Confidence: The smoke test builds confidence in build stability and gives a safe go-ahead signal for further testing.
4. Automation Compatibility: The smoke tests can be automated, thus saving time and reducing manual efforts in repeated executions.
5. Prevents Escalation: It helps in preventing the defective builds from going forward to the next stages of testing or deployment, protecting the test environment and production system.

Disadvantages of Smoke Testing:

1. Limited Coverage: Smoke tests cover only the basic functionalities and usually cannot show deeper, less obvious defects.
2. False Sense of Security: Passing smoke tests may give a false sense of security if the scope is too narrow, overlooking significant issues.
3. Maintenance of Test Scripts: An automated smoke test requires regular maintenance to keep the test scripts up-to-date when the software evolves, which can be resource-intensive.
4. Dependency Issues: Smoke testing failure in a multifaceted system may be related to the environment or configuration rather than a defect in the code. Thus, misdiagnosis may occur.
5. Time and Resource Consumption: The implementation and maintenance of an extensive smoke test suite is extremely time- and resource-consuming, especially for big projects.

What happens if Smoke testing fails?

The failure of smoke testing usually leads to the following actions:

1. Build Rejection: The build is rejected outright to prevent further testing or deployment.
2. Issue Notification: Developers are notified of the failure to begin quick fixes.
3. Debugging and Fixing: The development team at this stage debugs and fixes the issues that lead to the failure.
4. Re-testing: The corrected build is re-tested for its stability before it progresses.
5. Delay in Release Cycle: Continuous failures can delay the entire cycle of a project.
6. Resource Allocation: More resources may be needed to address the identified issues in the shortest time.

Smoke Testing vs. Other Testing Types

It’s important to distinguish smoke testing from other types of testing to understand its unique role:

• Smoke Testing vs. Sanity Testing: As both smoke and sanity testing are supposed to verify the basic functionality, smoke testing is broader, focusing on the whole build, while sanity testing is narrow, limited to some components upon certain changes.
• Smoke Testing vs. Regression Testing: Testing for regression is far more extensive and is meant to ensure changes haven’t had unfavourable impacts on already existing functionalities. Smoke testing is merely the preliminary check for basic stability.
• Smoke Testing vs. Unit Testing: While unit testing is performed at the code level, smoke testing deals with a high level that confirms if the core features of the application are working or not.

Below is complete comparison of smoke testing vs other testing types:

The Role of Automation in Smoke Testing

Automation forms the most vital part of smoke testing, especially in an environment where frequent builds are being deployed. Automated smoke testing scripts can quickly give a go or no-go verdict on the stability of a build, thereby saving precious time for the development team by giving instant feedback. This could be of especial help in agile and DevOps environments that practice continuous integration and continuous deployment(CI/CD).

Benefits of Automated Smoke Testing

• Speed: Since it is automated, tests will run faster compared to manual; even the feedback will be in real time.
• Consistency: Automation test runs consistently; hence, there is no chance of human mistake.
• Reusability: The test automation scripts, once developed, can be used across builds, thereby reducing time and effort.

At Testscenario, we specialise in creating robust automated smoke tests that integrate seamlessly into your CI/CD pipeline, ensuring that your development process is efficient and error-free.

Why Choose Testscenario for Smoke Testing?

At Testscenario, we understand the importance of smoke testing in ensuring the stability and reliability of your software builds. Our team of experienced testers uses the latest tools and techniques to conduct thorough smoke testing, identifying any critical issues early in the development process.

Conclusion

Smoke testing is a critical step in the software development process, offering an early indication of whether a build is stable enough to proceed with further testing. By catching critical issues early, it saves time, resources, and boosts the confidence of both developers and testers. Automation further enhances the effectiveness of smoke testing, making it an indispensable part of modern software development practices.

If you’re looking to streamline your smoke testing processes and ensure that your software builds are rock-solid, look no further than Testscenario. Our expert team is here to help you implement efficient and reliable smoke testing solutions that align with your business needs.

Ready to take your smoke testing to the next level? Contact us to learn more about our smoke testing services and how we can help you deliver high-quality software with confidence. Let us be your partner in ensuring that every build is a step towards success.