Negative Testing Should we do it

“Testing is the most essential phase of Software Development Life Cycle (SDLC). In fact, without proper and perfect testing, any application cannot be of superior quality. That is the reason why, Testers are also known as Quality and Assurance professionals. Tasting makes the application not only bug free but also stable and reliable one. Tester can find out how much potency the application has within itself and how it will act under different circumstances. Considering different requirements of testing, it is widely divided into two categories namely Positive Testing and Negative Testing. Today, our role is to discuss Negative Testing and its importance in real applications with special reference to Web application and desktop application.”

Negative testing for input field testing: While dealing with any software application, it is absolutely common to find many forms that need user inputs. Now, it becomes essential to test those input fields and this process is known as input field validation. As a tech savvy guy, you must aware of two types of input validation i.e. client side input validation and server side input validation. Both the sides are done by the developer; but it needs to checked thoroughly before moving it to the live stage. For the same, the tester needs to test each and every input field with contradicting values. For example, suppose, there is a field for Telephone number input. The tester needs to test whether it takes numbers in the field as a part of Positive testing. On the contrary, in Negative testing the tester tests if also takes Characters in the field, if takes more than 10 digits (i.e. to test if real telephone number or not) in the field etc. Again, he also needs to test the same for the server side validation i.e. after disabling JavaScript, does it takes characters or more than 10 digits into the database or not.

Negative testing for load time and response time: Performance of an application is as important as the quality of application. So, the application must be super fast and impart better user experience and for the same, the application must be tested properly and thoroughly. With Negative testing approach, the tester needs to test the application performance under different circumstances. It checks if the application able to fulfil the user requirement and does not crash or hang during browsing process. For the same, we need to test the load time of the application and obviously the response time should be considered. The tester puts as much load as possible on the server and tries to find out how the application exactly behaves under pressure. He makes multiple API calls and many server requests though the automation testing tool to check the load time of the application. If the application succeeds in the test then its fine else he fires a report for further enhancements.

Negative testing for exception handling: Exception is something that makes the application stop working. Suppose a user inputs 0 in the denominator of a calculator. What next? The result will be infinite and we can’t display the same. So in that case, there is usually a block of code written in the application to handle the exception or error and that particular block of code get executed when there is an exception. Usually there is a try block followed by catch for exception handling. Many times, the developer overlooks this scenario and hence forgets to put the try.. Catch block. So, it’s the duty of qualified testing/QA professional to find each and every exceptional case from the application with improper inputs and accordingly the exception is handled.

Negative testing for stability: Stability is one of the most important features of any application. If an application is not stable then it will be termed as a bogus application. Negative testing or we can say failure testing is the approach that enables an application’s actual strength by putting the application in wrong modes i.e. putting invalid data and trying to validate it anyhow. This needs typical creativity and patience so that, we can ensure if the application able to track the invalid data or not. By the end of the process, we can calculate or measure the stability of the application without much effort and hassle.

Negative testing for boundary value situation: Boundary value is the best possible error causing data that might be overlooked by the developer. Suppose there is an application that needs your age of activity should be between 5 years and 20 years. Then, the tester will try to check if it takes 20 year and 5 year of activities into the database or not; because, these two data are known as Boundary Values. So, the tester needs to check the boundary data as the input and the behaviour of the application for better result.

Negative testing to avoid data corrupt: As a software engineer, I can say anything in the database i.e. not relevant is like a bug. There should not be a single data entry into the database without any prior screening. Imagine a scenario, there is a field for First name in the database and we fine many numeric characters in those fields like Rnp34 or similar. Is it really a practical name in any manner? No, absolutely not. There are many hacker tries to enter bad data into your database, in fact they try to make it corrupt with bad or wrong data. But if the application is strong enough and is able to identify these types of invalid data then it will definitely stop them from the entry into the application server or database. So, its duty of the tester to check each and every prospective of the application and make sure that any user can’t enter a single bad or corrupt data into database.

Finally, it’s all about Quality Assurance!! As we already discussed, the chief aim of any tester or testing procedure is to make the application bug free and reliable one. The quality should be our primary concern from the very beginning. To achieve a quality end product, we have to follow many other testing approaches along with Negative testing. In fact, Negative testing is one of the testing processes that must be undergone before the production stage. Positive testing is a must and should be simultaneously performed along with Negative testing for an excellent end product i.e. stable, reliable and robust!!