What are the differences between Smoke Testing and Sanity Testing?

To give an overview, we will be overlooking an illustrated guide on  The uniqueness between Smoke testing and Sanity Testing, when should they be used, and why are smoke testing and sanity testing examples important.

What is Smoke testing?

Definition of  Smoke Testing

Smoke Testing, also known as “Build Verification Testing” and “Confidence Testing” is the first approach to software testing that occurs shortly following the release or creation of a software build. Its goal is to test the stability of the deployed software build by concentrating on some selected features of the system rather than the complete application. 

Smoke testing is the first test to be done in any new build. It can be performed by both developers and testers and it can be automated or performed manually. However, most smoke tests are carried out as automation testing. 

Purpose and Importance of Smoke Testing

Smoke testing is done to check if the basic functionalities of a software application are working correctly. It helps decide if the software should go through more testing or not. Doing smoke testing makes the overall testing process faster and helps to identify critical issues earlier. 

Here are some use cases of smoke testing.

• When releasing a new software build
• After a significant change to the application
• After feature improvements
• When releasing new features 
• After bug fixes
• After a new product deployment to the stage or production environments

Let’s look at an example use case where smoke testing is carried out. Take a simple scenario where there’s an application you need to log into and you’re able to send and receive messages. Once the application is built we need to test if the basic functionalities which are login, sending a message, and receiving messages are working. If those basic and most important functionalities of the application are not working or if the system is crashing even before getting to them, there’s no point in trying to test the additional features of the application such as deleting a message, editing a message, receiving status, etc. 

Process of Smoke Testing

The process of smoke testing can be divided into four main steps

• Preparing the Test Environment
• Selecting Test Cases
• Executing Smoke Tests
• Analyzing Results

Preparing Test Environment

To begin smoke testing, we first install the necessary tools, configure the software build, and configure the test environment. These are the preliminary tasks we do before we begin testing the critical functionalities of the software.The test environment needs to be configured in a way so that the testing would be efficient and also the test environment needs to be set up in a way as close to the production environment to ensure the accuracy of the smoke test.

Selecting Test Cases

The next stage in smoke testing is to pick which test cases to use after the test environment is ready. These test cases focus on the software’s major functions and are selected based on their importance and the likelihood of detecting product bugs.

Executing Smoke Tests

The smoke test needs to be done for the selected test cases. Systematically executing the tests denotes that the same order should be followed each time and the test results need to be recorded. Smoke testing can be automated or done manually.

Analyzing Results

The final step after the execution of the smoke test is to analyze the results. By analyzing the test results the tester or the developer will identify if there are any defects found and will determine if the software is eligible for further testing or release. If there are any defects found, they need to be fixed and repeat the smoke tests with the new fixes until there are no more blockers or critical-level bugs.

Key Features/Characteristics of Smoke Testing

Some key features and characteristics of smoke testing are explained below.

Covers the product yet shallow in scope -We normally examine if the program is operating smoothly, test its core functionalities, and search for any noticeable defects or errors. Depending on the software and its requirements, the precise areas addressed in smoke testing may differ. In general, we concentrate on testing the application’s most significant functions and features.

Priority-based test Case selection – Test cases are selected based on the order of priority. The test cases should cover the basic functionalities and the areas that are most likely to be defective. 

Less time and effort  – Smoke tests are quick and easy. Therefore, they are executed in a less amount of time and the results will be available quickly as well.

Non-exhaustive – As the smoke test does not cover the entire application and has shallow and wide test cases, smoke testing is non-exhaustive.

Can be automated – This means the developers or the testers do not have to perform smoke testing manually. They can use a test tool and automate the entire process which will save time. This helps to reuse the automation scripts to test the products continuously. 

Focus on critical paths – Similarly, as the smoke test should cover the most important functionalities of the application, it focuses on critical paths and checks if the software is ready for release.

Best Practices for Effective Smoke Testing

For the smoke testing to be effective the tester needs to ensure most importantly the test covers all the basic and important functionalities of the application and the test cases are selected based on their importance and prioritized based on the likelihood of finding defects.

Therefore some of the best practices to ensure the above are using a test framework, automating smoke testing whenever possible, performing the test as early as possible in the software development process, fixing defects as soon as they’re found, and documenting test results for later review. 

What is Sanity testing?

Definition of Sanity Testing

Sanity testing is done to check if specific changes or features in a software build are working correctly. It is different from smoke testing because it focuses more on verifying smaller changes and functionalities rather than the overall stability of the software. Sanity testing is a type of regression testing that is more focused and specific. Usually, these narrow and deep tests are performed only by the testing team. Furthermore, sanity testing saves time and effort by focusing on testing the improved components rather than the full product. 

Purpose and Importance of Sanity Testing

Sanity testing is done to ensure that end-to-end testing of a build can proceed smoothly after making minor changes or modifications to the product. This is carried out before proceeding to more complex test rounds. It focuses on individual application capabilities, allowing us to see if the code modifications have introduced any new bugs without having to test the entire system. This saves time and effort while assuring that the improved components are stable. It is important as it can help to prevent costly delays and disruptions to the development process. 

When to use Sanity Testing

This can be used on a new build or a build after several regressions. It is also used after either a minor or a major change is made to the code, after bug fixes, for quick product stability checks, after recent changes to a specific component or feature, and before the build is released to production or the customer.

Consider a software application with a login page, signup page, and home page. Assume applications login flows got recently changed. Hence a sanity test can be performed to cover the login functionalities to verify the login component. For example, when setting the password to the application, the user needs to follow some specific guidelines such as it is mandatory to have 8 characters, at least one number, etc. This can be tested with sanity testing and if the software allows a user to set a password that does not follow the given rules it is an issue and it should not be allowed. Therefore the sanity test has failed and the testers will inform the developers about this issue and need to get it fixed before the release.

Process of Sanity Testing

The process of sanity testing can also be divided into four main steps

• Preparing Test Environment
• Selecting Test Cases
• Executing Smoke Tests
• Analyzing Results

Preparing Test Environment

The test environment should be as close to the production environment. To prepare the test environment, you need to set up the hardware and software required for testing. When setting up the test environment, it should be isolated from the production environment so that any problems that occur during testing wouldn’t affect the production environment and data may not be lost. 

Selecting Test Cases

After preparing the test environment, the test cases need to be selected. The selection is done by focusing on the most critical features of the software and the test cases should also be able to catch major problems early on. The importance of the feature, the likelihood of the feature being used by the users, and the complexity of the feature also need to be considered when selecting test cases. 

Executing Sanity Tests

Sanity tests are executed in a fast and efficient manner. The execution should be done in a logical order and the results should be documented.

Analyzing Results

The documented results need to be reviewed and analyzed to identify major issues with the software. If any issues are found, the software will be redirected to the development team to be fixed.

Key Features/Characteristics of Sanity Testing

Narrow Scope and Coverage – Sanity testing has a narrow and deep scope. The coverage is not much as it focuses on a limited set of features or some selected components which are the most important ones and does not cover all the features and functionalities of the software. 

Test Case Selection is based on Importance – Test cases in sanity testing are selected mostly based on the importance of the feature. Selection depends on their importance, likelihood of use, and complexity. This allows you to concentrate on important areas while also ensuring that the essential functions are working fine.

Less Time and Effort Constraints – Because it does not take much time or effort to be carried out, sanity testing is considered a fast and high-level test. It focuses on confirming the critical functionalities and changes, allowing for more efficient testing in less time. Usually, it takes a few hours or days to perform.

Involves Rapid Decision-Making – During sanity testing, testers are responsible for finding any issues and reporting them to developers as soon as possible. This involves testers taking quick decisions regarding the software, and assessing if it is working as expected or not. Their analysis results and reports have an important role in ensuring that the product fulfills the required requirements.

Complementary to Other Testing  – Sanity testing is used alongside other testing types like unit testing, integration testing, and system testing. It is frequently used when combined with regression testing. The goal of sanity testing is to reveal any issues that other testing methodologies may have missed, thereby ensuring that the software is in excellent working order.

Best Practices for Effective Sanity Testing

There are many best practices to follow in order to ensure efficiency in sanity testing. Some of them are defining the scope properly, selecting the right test cases, making sure the test environment is similar to the production environment but isolated from one another, and using the results to improve the test cases. 

There are numerous ways that can be used for more effective sanity testing. One such strategy is to use test automation, which helps to streamline and optimize the testing process. Working closely with the development team is a must since they have great insights into the product features and possible test cases. Furthermore, ensuring clear and efficient communication of test results is critical in order to resolve any identified bugs as soon as possible. By combining these principles, sanity testing becomes more successful, resulting in higher-quality software releases.

Pros and Cons of Smoke Testing and Sanity Testing

As we discussed what smoke testing and sanity testing are, let’s look into some pros and cons of these two testing techniques.

Pros of Smoke Testing

• Early detection of major issues: as smoke tests are done at the very early stage of the software development process, they can identify and prevent problems.
• Time and cost efficiency: smoke tests are quick and efficient in detecting problems therefore can save time and money by preventing further testing if there’s an issue with smoke tests. 
• A quick assessment of application stability: the main purpose of smoke tests are to identify if the software is stable to move forward with the development process, and assessment of the application.
• Identifies critical failures before extensive testing: without smoke testing, developers may not be able to identify major issues and will send the application to the testers to perform extensive testing With smoke testing developers can run a smoke test before delivering it to the QA team.
• Provides confidence in build quality: this can help in ensuring the software is released in a high-quality state as it increases the confidence in the build quality.

Cons of Smoke Testing

• Limited test coverage: smoke tests cover only the most critical features.
• Potential for false positives: smoke testing tends to identify problems that are actually not problems and this may waste time.
• Reliance on predefined test cases: smoke tests do not use all the test cases in a test suite, therefore some problems may not be identified.
• Not a substitute for comprehensive testing: comprehensive testing is performed to identify most of the problems in an application. This is not possible with smoke testing.
• May miss minor defects or edge cases: this may also happen because the test only covers the critical features.

Pros of Sanity Testing

• Focuses on specific areas or functionalities: sanity testing focuses on specific areas and helps to ensure they work right.
• Quick evaluation of stability and functionality: sanity testing is used to evaluate the stability and functionality of the software quickly.
• Time and resource efficiency: as it focuses only on the most critical areas the test can be efficient.
• Confirmation of critical fixes or enhancements: tests can be used to confirm that critical fixes and enhancements are working properly.
• Complementary to other testing techniques: as sanity testing is complimentary it can ensure the software is thoroughly tested.

Cons of Sanity Testing

• The narrow scope of testing: sanity testing may not identify all problems with the software as it focuses only on specific areas.
• Limited test coverage: as it focuses on critical features or components its coverage is limited.
• Potential for missing unrelated defects: as the test focuses on major problems minor issues may be missed.
• Reliance on selective test cases: sanity testing does not cover the entire software.
• Not a replacement for thorough testing: thorough testing should be performed to identify most of the problems with the software and sanity testing doesn’t do that.

Difference between smoke and sanity testing

 

While smoke testing and sanity testing are both conducted during the early stages of software development, they have distinct differences. The primary distinction lies in their approach: smoke testing is a broad and shallow test, covering a wide range of functionalities, whereas sanity testing is narrower and deeper, focusing on specific areas of the software.

The following table shows a summary of smoke testing vs sanity testing.

Feature	Somke Testing	Sanity Testing
Purpose	To verity that the software con start up and run its basic features	To verify that software is working as expected
Scope	Hight-level	Narrow
Produc Documentation	Not Required	Required
Who performs it	Developers or Testers	Testers
When is it performed	Before sanity testing	After somke testing

 

Hence, Smoke testing ensures that the software is stable enough for further testing, whereas sanity testing verifies the general functionality and integrity of the software after changes or modifications.

Importance of both Smoke Testing and Sanity Testing

As demonstrated by the examples of smoke testing and sanity testing, both play vital roles in assuring the quality of software. These tests aid in identifying any major defects or regressions in the software, allowing for fast fixing and enhancing the overall quality of the product.

Importance of Smoke Testing

Smoke testing can help to identify major problems with the software early on, such as crashes, errors, startup issues, and missing features. This can help to prevent the software from being released with major problems that would affect users. It can also improve the software quality.

Therefore, smoke testing is really important when it comes to testing in the early stages of the software development process.

Importance of Sanity Testing

Sanity testing can help to identify minor problems with the software early on, such as typos, edge cases, negative flows, UI issues, and minor bugs. This can help to prevent the software from being released with minor problems that would affect the user experience of your users. It can also contribute to saving money and time as well as improving the software quality.

Conclusion

Being a test engineer, it’s no doubt that you have worked with testing types such as smoke and sanity. However, many IT professionals like developers lack a clear understanding of the differences between them. Therefore, with this article, we aim to share what smoke testing and sanity testing are, why they are important for you as an IT engineer, and why you should be aware of their pros and cons.

When a release comes, the release team gets together and prioritizes the testing types to be carried out based on the timeline. During such prioritization, most of the time people prefer to conduct a smoke testing round to verify the stability of the product. The sanity test will be picked to be carried out as a second round of testing as it focuses more on testing a specific improved component of the product and not the overall product.

It is necessary to conduct other types of testing, such as regression, performance, and security testing, to ensure the product’s quality before its release.