Testing is one of the most time consuming and exhaustive phases of software development, be it manual testing of web-based applications or automation testing.

This is because testing is the best way to achieve quality assurance and test teams spend lots of time on testing the product with various methods and tools to find out and correct all the defects and to make sure a customer does not report it.

While we have heard of several testing techniques, such as load testing and performance testing, one technique which many testers are unfamiliar with is negative testing.

But what is it and what benefits can it bring?

We will cover everything you need to know in this article.

So, let’s take a look at them now.

What Is Negative Testing?

A successful test case is one that uncovers a previously unknown defect. This includes all possible defects under all possible input conditions and includes invalid input conditions.

While supplying valid input conditions helps you see whether the system delivers its functionality correctly, supplying invalid input conditions helps you make sure the system functions only in the way it is intended to and all the exceptional conditions are handled with grace.

The type of testing where the software product is tested with abnormal situations and conditions is known as negative testing and it is as important as positive testing for establishing the quality of a product.

Negative Testing Paths

There may be many types of testing, such as unit testing, black box testing, stress testing, beta testing, smoke testing and manual software testing, but all types of testing fall under one of two categories: positive testing paths and negative testing paths.

On the one hand, positive testing is the most general and widely applied testing methodology where a user performs valid operations on the application to find out whether it is working properly according to its specifications. It involves the use of only correct and valid data.

There may be more than one alternative path to arrive at a particular result and all these testing scenarios will fall under positive testing.

On the other hand, negative testing is where the system is intentionally supplied with error conditions to check its robustness and stability. It is also known as error path testing or failure testing.

There is no limit to the number of test cases or test scenarios that you can use for negative testing. Anything that is not a valid input can be used and hence you can apply all your creativity to testing your application.

Why Is Negative Testing Necessary?

While positive testing establishes the functionality of the product, negative testing ensures the functional reliability of the product and both are mandatory to assess the quality.

The following are some of the benefits of negative testing:

  • – It helps in quantifying the functional reliability.
  • – It helps determine the extreme conditions under which the system crashes.
  • – It assists in uncovering serious flaws in the exception handling mechanisms followed by the system.
  • – It ensures that the application validates the data correctly and handles invalid data in the right way.

Negative testing is a basic necessity since many users tend to apply the wrong information or invalid data into your application either accidentally or intentionally. You should be able to ensure your application does not crash or stop working.

It has to deal with all the unprecedented inputs in a graceful manner and should satisfy all the quality and security concerns. For this purpose, you must know whether your application can handle the exception cases efficiently and is able to recover from error conditions effectively through negative testing.

Optimizing Your Negative Testing

As we mentioned earlier, there is a limitless amount of possible negative test cases and testing your application for all these will be very difficult. But, by applying certain optimization techniques, you can reduce the vast number and still achieve sufficient testing to establish your product’s quality.

Here are two ways to optimize your negative testing.

  • – Boundary Value Analysis

Boundary refers to the limit of the range of accepted values. Thus, anything above or below the boundary is considered invalid. You can only apply the on boundary and near to boundary values to test your application. For instance, in an age scenario, you can apply boundary value analysis for maximum effectiveness through:

  • – On boundary: 10, 50
  • – Below boundary: 9, 49
  • – Above boundary: 11,51

Here, nine and 51 are the only required negative test cases.

  • – Equivalence Class Partitioning

This is another method that can assist you in optimizing your test cases. The range of accepted and unaccepted values or conditions is divided into classes and testing one value from each class is considered sufficient and the results are considered equal for all the other values in the class.

By now, you must understand what negative testing is and why it is important.

However, if you plan to implement negative resting, it is advisable that you get help from a software testing company that has extensive experience in several testing techniques across multiple technologies, such as manual testing of mobile applications or automated testing service as per your needs.

So, when do you plan to incorporate negative testing? Do you have any questions? Please feel free to leave your comments below and thanks for reading!