A Complete Guide to Negative Testing in Software Testing
Negative testing spots the negative characteristics of the application
Join the DZone community and get the full member experience.Join For Free
Software testing is vital because it allows you to test if an application is working properly. There are various types of tests that you can perform if you work in the software industry.
Nevertheless, all these tests fall under one of these two classifications: positive and negative testing. Both categories are equally important, but positive testing is more popular than negative testing.
Find out what is negative testing in software testing. Learn why testers usually avoid performing negative tests in this blog. Discover how to perform negative testing in practice and what negative testing scenarios you can expect. Understand what the difference is between positive and negative testing. Finally, explore the benefits of negative testing in the following sections.
What Is Negative Testing?
Software testing is the process of checking if the basic functions of your software program work correctly according to its design. At the same time, it verifies if the application is equipped to handle challenging situations and invalid inputs.
Negative testing refers to the negative approach to software testing. It is also called failure testing or error path testing. It aims to spot the negative characteristics of the application by designing test cases. It reveals how the program responds to invalid data. It gives you the chance to compare the expected output against the incorrect output.
Why Do Testers Avoid Performing Negative Tests?
Despite its usefulness, negative testing seems to have a negative reputation among software testers. A lot of professionals are hesitant to perform negative testing because they believe it may unnecessarily cause a delay in the launch of the software product.
Some testers consider it as a distraction that wastes time and resources. They are convinced that it is better to pour their efforts into positive testing instead.
The lack of skills and knowledge about negative testing also hinders testers from employing it. Not everyone understands completely how the software works and what its limitations are.
However, despite its name, negative testing leads to positive results. It should be an essential part of your software testing strategy for the following reasons:
Your company is responsible for offering an excellent software product to the clients. Negative testing, in tandem with positive testing, is necessary to ensure the stability of your application. You may not be able to guarantee that your program is completely free from errors, but you must at least do your best to minimize failures via negative testing.
Your clients have entrusted software projects to your company because they believe you are capable of creating excellent software products. High-quality software is especially important if it is related to online stocks, e-commerce, and other sensitive business matters.
Negative testing is crucial if you aim to attain client satisfaction. Still, it is up to your clients to decide if they are willing to invest in the extra expenses necessary for negative testing.
How To Perform Negative Testing in Practice
These are some of the smart techniques that you can utilize to perform negative testing on software applications:
Boundary Value Analysis
This method involves writing the test cases for values that are outside the boundary limits. For instance, your boundary limits are 1 to 100 in case you are testing a text field that accepts data within the 1 to 100 character range.
It is a technique that tests the functionality of a software program. It entails grouping the input values into various partitions. You will be testing some values in every partition.
This procedure pinpoints the specific conditions which trigger failure or error messages. If possible, you should try to identify and correct the issue without a system crash. In some cases though, an incorrect result may lead to an extreme “downstream” failure if the error condition is not immediately noticed and addressed.
It is a basic but crucial method that documents error conditions that you are planning to test. A software testing checklist is commonly used in tandem with error guessing.
If there are design patterns, anti-patterns are their antithesis. If the former is the best way of resolving an issue, the latter is a solution that does not work. Anti-patterns are the ideal source of negative tests.
This technique is used to increase your knowledge about the application while the test is ongoing. It may be conducted simultaneously with other tests. Exploratory testing can show you a clear picture of which aspects of the application work and what doesn’t.
Small Scale Test Automation
It is a method that uncovers memory errors, code defects, and other issues that are occasionally revealed in production use. It entails performing the same action thousands of times to see its effect on the program.
This procedure involves the input of random data which may cause unexpected failures, crashes, and issues. In this case, there are no preset expected results, unlike other negative test cases. It is simply an observation of what may potentially occur because of arbitrary inputs.
State Transition Testing
It is a technique that is utilized to spot defects in the application. It originates from the concept that software can only exist in one particular state at one point in time. For instance, a program is considered to be in its normal state until an issue reveals itself.
Negative Testing Scenarios
The purpose of negative testing is to pinpoint possible application failures in different circumstances. Here are some of the potential situations where errors and crashes may unexpectedly occur:
Populating Required Fields
There are certain software and web pages which showcase fields that are required to be filled up by the user. You can design a test that leaves the required fields blank so you can evaluate the program’s response to this scenario.
Correspondence Between Data and Field Types
Most digital forms and dialog boxes are capable of receiving data in a certain form, such as text, number, date, and time. You can make a test where the wrong data type is entered into a control to see how the application reacts in this case.
Allowed Data Bounds and Limits
Some software programs include input fields that only receive data that falls under a particular range of numbers or text. You may design a test which inputs a value that is lower or higher than the boundaries of a particular field.
Allowed Number of Characters
There are web pages and applications with fields that only permit a limited number of characters to be entered by the user. You have the option of conceptualizing a test where more characters are entered in the field than is normally allowed.
Web Session Testing
Certain web browsers require the user to log in first before it loads web pages. You can prepare a test which attempts to open web pages in the application without logging in beforehand.
Some programs and web pages feature fields with a reasonable limit. You can make a negative test that inputs invalid data in the field.
Difference Between Positive and Negative Testing
In contrast to negative testing, positive testing is a type of software testing which ensures that the application is working properly under normal circumstances. This table gives you an overview of the main differences between positive and negative testing:
Benefits of Negative Testing
Positive testing has its advantages, but negative testing has its crucial benefits as well. These are just some of the perks of negative testing software applications:
Negative Testing Helps Identify Incorrect Bug Processing
It allows you to avoid application failures caused by faulty bug processing. It helps you to confirm if the software code stopped managing a programmed use case. It can also prevent situations where the client is unable to access data that is necessary for bug fixing.
It Helps Identify Possible Weak Spots in Security
Negative testing allows you to ensure that a client cannot access a personal account in the program in case he or she is not permitted to do so by the organization. It enables you to prevent a group of users from using specialized functions of the application if necessary.
It Helps Maintain a Clean Database
The database of a program will be in good condition if it only includes valid data. Negative testing can increase the possibility that only valid information is stored and displayed by the application.
Published at DZone with permission of Vakul Gotra. See the original article here.
Opinions expressed by DZone contributors are their own.