Flipping the Script: A Guide to Negative Testing
What is Negative Testing?
As software continues to evolve, so do the ways in which it's put through its paces for functionality and performance. While many folks are knowledgeable about positive testing, where testers validate that the software behaves as expected when given valid input, there's another side to the coin that's just as important: negative testing.
This type of testing involves intentionally providing invalid or unexpected input to see how the software reacts. By flipping the script and thinking outside the box, negative testing can help uncover hidden bugs and ensure that software is robust and able to handle unexpected scenarios.
Ensuring that software is functional, reliable and free from bugs is critical to the success of any application or system. While positive testing is a common approach to validate software by providing expected input, negative testing is another essential technique that should be considered. By intentionally providing unexpected or invalid information to the software, negative testing can help uncover hidden faults that positive testing may miss.
In this blog, we will explore the art of negative testing, its significance and techniques to help you become a master of uncovering faults in your software. We'll examine positive testing vs negative testing, a step-by-step guide, and real-life examples for incorporating it into your software testing strategy.
Also Read: What is Performance Testing?
Positive and Negative Testing: Exploring Both Sides
Positive and negative testing strategies are two complementary techniques for software application testing for quality assurance and proper functionality. Although negative and positive testing approaches differ fundamentally, their objective is identical: anticipating user behaviour, testing edge cases, finding bugs and improving application quality.
Positive testing aims to verify that your application functions as anticipated. Any error detected during this form of testing results in a test failure.
On the other hand, negative testing ensures that your application can appropriately handle invalid inputs or unexpected user behaviour. For instance, if a user enters incorrect data or misses something out entirely, negative testing ensures that the application responds appropriately and fails gracefully.
This type of testing also helps identify potential vulnerabilities, weak points and flaws in user experience, improving the application’s overall quality.
However, it is essential to note that negative testing cannot be regarded as a replacement for positive testing as both techniques are critical to ensure comprehensive testing and a high-quality product.
Positive testing looks at what an application should do, while negative testing throws in unexpected anomalies to check if the application can handle them. The latter, therefore, involves expecting any exceptions that could occur.
Exceptions are expected during negative testing since they demonstrate that the application correctly manages improper or unaccounted for user behaviour. Combining positive and negative testing methods is regarded as good practice and this strategy results in higher test coverage and exploration of greater edge cases, driving a higher return-on-investment in your testing practice.
Also Read: Software Quality Management Best Practices
Step by Step guide to Negative testing
Outlined below are the essential steps for conducting a negative test:
Identify the specific feature or functionality to be tested, such as data validation, error handling, or security checks.
Determine the criteria for a negative test that deliberately causes the software to fail or produce unexpected results. This could include inputting invalid data, exceeding maximum limits, or performing actions out of sequence.
Create a test case that includes the steps required to reproduce the negative test, including the input or actions that will trigger the negative scenario and any expected outcomes.
Set up the test environment to ensure the system is in a state where the negative scenario can be executed. This may require specific data or configurations.
Execute the negative test by following the steps outlined in the test case to reproduce the negative scenario.
Observe and document the test results, comparing the actual outcome to the expected outcome outlined in the negative test case.
Report any defects or issues during the test, providing a detailed description of the problem, the steps required to reproduce it, and any relevant logs or error messages.
If necessary, repeat the test with different input data or variations on the test case to explore potential failure scenarios further.
Real-Life Negative Testing Scenarios
Invalid Input: Testing how the software responds when invalid input is entered is a crucial negative testing scenario. For example, entering non-numeric characters in a field that expects only numbers, or entering a value outside the acceptable range, such as an invalid date or time format.
Error Handling: This includes testing for how the software responds when it encounters unexpected errors, such as system crashes or network failures, as well as testing for how it handles expected errors, such as insufficient memory or disk space.
Security: It can also include testing for security vulnerabilities and how the software handles malicious attacks or responds to things such as SQL injections, cross-site scripting (XSS), and buffer overflows. Here we can see how the software handles sensitive information, such as user passwords or credit card data, and protects against unauthorised access.
Also Read: What is the Automation Testing Pyramid?
Bottom Line
To sum up, negative testing is an essential aspect of software testing that works hand-in-hand with positive testing to ensure the functionality and dependability of software applications. By deliberately inputting invalid or unexpected information, negative testing helps uncover concealed bugs and vulnerabilities that may not be found through positive testing alone.
As described in this guide, negative testing involves identifying particular features or functionalities to be tested, defining the criteria for negative tests, generating test cases, conducting the tests, and reporting any defects or issues that arise. Integrating negative testing techniques into your software testing approach can enhance your software applications' overall quality and resilience, making them more dependable and secure.