2024 Smoke Testing Guide

As we move through 2024, early-stage quality assurance methods ensure you meet the changing software development landscape. As a preliminary test phase, smoke testing verifies that the application’s functionalities work as expected after updates or integrations. 

This article will explain why smoke testing is important, as well as practical applications, examples, and best practices for smoke testing in the early stages of development.

What is Smoke Testing?

Smoke testing is a type of software testing that involves running a set of predetermined tests on a build, usually after a significant change or addition to the software. Smoke tests are designed to quickly determine whether a program’s most critical functions work without focusing on finer details.

Where smoke testing sits in the SDLC

The term “smoke testing” is derived from the concept of “smoke and mirrors,” which refers to focusing on basic functionality rather than diving deep into all features and functionalities. Originally applied to hardware, the term has also been applied to software. The intention is to run the application for the first time and see if it “catches on fire.” 

Smoke tests evaluate whether an application or system’s critical functionalities work as expected. For example, 

  • Does the software start successfully?
  • Is the user able to log in?
  • Are the main features accessible?

Why You Need Smoke Tests

Bugs cost exponentially more when found in the later stages of the software development lifecycle. Early detection of bugs saves time and effort and reduces the overall development cost. Fixing a bug in the early stages of development is usually simpler and less time-consuming than fixing a bug in later stages.

By running a set of predetermined tests on a build, smoke tests allow DevOps teams to find and fix issues before they impact customers. It acts as a first line of defense, catching major issues that could severely impact the software’s functionality.

Smoke Testing Examples

Smoke testing is a preliminary check to identify major issues early in the development cycle, verifying the build’s stability for further testing. 

Let’s explore a real-world example of smoke test cases:

Login Functionality Verification:

Imagine you’re testing a newly developed web application. One critical feature is user authentication, ensuring only registered users can log in with valid credentials.

In a smoke test, you would verify the following:

  • User Registration and Login: Confirm that users can register and log in using their credentials.
  • Authentication Flow: Check if the login process follows the expected steps (e.g., entering username and password, clicking the login button).
  • Error Handling: Validate that appropriate error messages appear for incorrect credentials or other login-related issues.

If these core functionalities pass the smoke test, the application is stable enough for further testing.

Benefits of Smoke Tests in Software Testing

Catching Major Issues Early

One of the primary benefits of smoke tests are their ability to catch major issues early in the software development lifecycle. Through smoke testing, you can identify major problems that could affect the software’s performance or usability.

This early detection allows teams to address these issues before they become more complex and harder to fix.

Preventing Wasted Effort

Smoke testing helps prevent the wasted effort of conducting further, more detailed tests on an unstable build. If the smoke test fails, the build is not stable enough for further testing. 

This allows the development team to fix the major issues first, ensuring that the subsequent testing efforts are not wasted on a fundamentally flawed build.

Time and Cost Savings

Smoke testing can save significant time and cost by catching critical defects early on. The earlier a defect is found, the cheaper it is to fix. 

This is because early-stage defects impact other parts of the system less, and fixing them requires less effort in bug fixes and retests. This can lead to a more efficient and cost-effective development process.

Confidence to Stakeholders

Finally, smoke testing provides stakeholders confidence that the software is dependable for further testing and evaluation. A successful smoke test indicates that the software’s basic functionalities are working as expected, which can give stakeholders confidence in the stability and build quality. 

This can be particularly important in agile environments, where builds are frequently released for testing and evaluation.

Disadvantages of Smoke Tests

While smoke testing is a valuable tool in software testing, it’s important to acknowledge that it has limitations and may not uncover all defects. 

Here are some of the disadvantages of smoke testing:

Limited Coverage

Smoke testing focuses on the system’s most critical functionalities. While this approach effectively catches major issues early, it may not uncover all defects, especially those that are less obvious or located in less frequently used system parts.

Possibility of False Negatives

There’s a possibility of false negatives, where the smoke test passes but other critical bugs still exist. Smoke tests are designed to be broad and shallow, focusing on the main features without going into detail about each one.

Therefore, while a successful smoke test can provide confidence in the build’s stability, it does not guarantee that the software is bug-free.

Minor Issues May Go Undetected

Since smoke testing prioritizes identifying significant issues, it could leave minor issues undetected until later stages. If accumulated, these minor issues could lead to substantial problems over time. 

Smoke Testing VS Other Testing Methodologies 

Smoke testing vs other testing Methodologies

Types of Smoke Testing

  • Manual Testing: In manual smoke testing, human testers run a predetermined set of tests without using automated tools. Testers manually interact with the software’s interface, ensuring the essential capabilities work as intended. This method is widely used and relies on manual efforts to ensure stable builds.
  • Automated Testing: Automated testing uses software testing tools to automate the smoke testing process. It is much faster; once the test is created, you have to click a button to run all your smoke tests simultaneously. You can get results in a few minutes instead of waiting a few hours for a team of testers to complete manual testing.
  • Fused Software Testing: Fused software testing helps you tackle builds as they are packaged and deployed by CI/CD, feature flags, and other systems. As build criteria are met, fused software testing initiates automated tests and sends signals to manual testers when warranted.

In addition to these, there are a few more types of smoke testing:

  • Daily Smoke Testing: Daily smoke testing entails conducting smoke tests daily, particularly for projects where the development process includes frequent builds and continuous integration. It helps to make sure every daily build satisfies minimal requirements for quality.
  • Acceptance Smoke Testing: Acceptance smoke tests determine whether the software meets the stakeholders’ or end users’ requirements and specifications. They are typically run after the complete development phase and before the software is released to the end users.
  • UI Smoke Testing: UI smoke testing focuses only on an application’s user interface components. It checks that the fundamental user interface elements and interactions operate as intended.

Smoke Test Cycle

Smoke testing cycle

The development team delivers a build, which QA passes for an initial smoke test. Then, a list of test cases based on core or key features is prioritized, tests are created, and the software is tested.

What Happens If a Smoke Test Fails?

If smoke testing fails, it indicates that the newly created or improved software/system has critical issues that must be addressed. The testing team will stop further testing and may release an interim report to fix existing issues. They can insist on developer testing for the further cycle. The smoke testing test cases can be shared with the developer team to understand the issues better. As a result, significant issues are addressed early in the development cycle, preventing the waste of resources and time on an unstable build.

Therefore, a failed smoke test is not a setback but a valuable feedback mechanism guiding the development process toward a more stable and reliable software product.

How To Perform Smoke Testing

Smoke testing is an integral part of the software development process. Let’s dive into the steps required to perform smoke testing:

  • Step 1: Identify the Scope: The first step in smoke testing is to identify the scope of the testing. This involves determining the software’s most critical functionalities that need to be tested. For example, in a banking application, the key features could be login, account balance check, and fund transfer.
  • Step 2: Create Test Cases: Once the scope is identified, the next step is to create test cases. These test cases should cover the critical functionalities identified in the first step. For instance, for the banking application, a test case could be: “Verify that a user can successfully log in with valid credentials.”
  • Step 3: Execute Smoke Tests: After the test cases are created, they are executed. This can be done manually or using automated testing tools. The goal is to check whether the critical functionalities work as expected.
  • Step 4: Analyze Results: The smoke test results are then analyzed. This involves checking whether the tests passed or failed and determining their implications.
  • Step 5: Report and Communicate: The findings are reported and communicated to the relevant stakeholders, such as developers, project managers, and quality assurance teams. This helps make informed decisions about whether to proceed with further testing or fix the issues identified during smoke testing.

Automated Smoke Tests

Automated smoke testing has several advantages that make it a valuable part of the software testing process:

  • Increased Speed: Automated smoke tests can be run quickly and provide immediate feedback on a system’s basic functionality. This allows developers to identify and fix issues early in the development process.
  • Improved Accuracy: Automated tests execute the same steps precisely every time they are run. This eliminates the risk of human error and ensures that the results are accurate and reliable.
  • Improved Repeatability: Automated smoke tests can be run as often as needed. This is particularly useful in agile development environments, where changes are frequently made.
  • Integration with CI/CD Pipelines: Automated smoke tests can be integrated into Continuous Integration/Continuous Delivery (CI/CD) pipelines. This means they can be run automatically whenever code is pushed to the repository, providing immediate feedback to the development team.

Conclusion

Smoke tests are the first line of defense in software quality assurance, providing quick feedback on a build’s health. Whether through manual methods, automated tools, or a hybrid approach, smoke testing verifies key functionalities. 

By implementing regular smoke tests, development teams can avoid the wasted effort of advancing with unstable builds and maintain a steady pace in the development cycle.

For teams aiming to optimize their smoke testing strategies and ensure high-quality software delivery, collaborating with an experienced expert like Testlio can be highly beneficial. Testlio specializes in comprehensive quality assurance and testing services that prioritize high-quality outcomes.

To learn more about how Testlio can support your software testing needs and enhance your project’s success, visit our website: Explore Testlio’s services.