The Power of Negative Testing in Improving Software Quality

It’s no secret why software testing is important in today’s testing landscape. It helps to ensure the quality, reliability, and usability of the applications. It’s an essential step in the software development process that helps to identify defects, ensure compliance with standards, and enhance the user experience.

Positive testing and negative testing are two types of software testing methodologies used to validate the functionality of a software application.

What is Positive Testing?

Positive testing is a type of testing that focuses on verifying that the software behaves as expected when it receives valid inputs. For example, if a software application is designed to add two numbers, positive testing would involve inputting valid numbers and verifying that the correct result is obtained.

While you may be well aware of the necessity of positive testing, most of us underestimate the significance of negative testing.

So what exactly is Negative Testing?

What happens when the system receives invalid inputs? How will the system react?

For the same example where a software application is designed to add two numbers, negative testing will involve inputting invalid numbers such as alphabets, symbols, or special characters, and verifying that the software generates an error message instead of providing an incorrect result.

Negative testing, also known as  “failure testing” or “error path testing”, is a crucial aspect of software testing. It involves evaluating a system’s ability to identify and prevent potential failures, errors, and security breaches that can occur in real-world situations.

Example scenarios involve sending in an empty form, inserting data outside of a form field’s permissible range, or attempting to access a protected resource without the proper authorization.

The ultimate goal is to ensure the system behaves as expected, delivers the appropriate error messages, and is capable of handling error scenarios and incorrect inputs, ultimately leading to a more reliable and robust software product.

Automate testing for your web application in THREE days. Start Free Trial Now

Key Differences between Positive Testing and Negative Testing

A thorough software testing approach must include both positive and negative testing since they help to ensure that the software is functional, reliable, and secure.

They both have different objectives and concentrate on various facets of a system’s behavior.

	Positive Testing	Negative Testing
Focus of Testing	To ensure that a system behaves correctly under expected circumstances and in response to valid inputs.	To verify that a system behaves correctly when it receives invalid inputs, operates under unusual conditions, or encounters unexpected events.
Goal	Confirmation that the system meets its requirements and performs its intended functions correctly.	Identification of any weaknesses or defects in the system and ensure that it can properly handle error conditions and unexpected inputs.
Input	Valid data input	Invalid data input
Output	As expected/defined in requirements	Appropriate error messages or response
Test Coverage	Does not cover all possible scenarios	Covers all possible scenarios

How to identify negative test cases in software testing

Identifying negative test cases in software testing entails coming up with novel ways to expose a system to invalid inputs, unusual conditions, or unexpected events, and then designing test cases to validate that the system responds correctly in these situations.

Here are some steps to help you identify negative test cases:

1. Review the system’s requirements and specifications: Gain an understanding of the expected inputs and conditions. This will help you establish the boundaries between what is acceptable and what is not.
2. Consider edge cases: Edge cases are inputs or conditions that are at the boundaries of what is considered valid. For example, the largest or smallest input that can be accepted, or the conditions that exist at the limits of what is considered normal.
3. Think about error conditions: Consider the various error conditions that can occur, such as invalid inputs, network outages, or resource unavailability. Create test cases to validate that the system responds appropriately in these situations.
4. Consider security implications: Consider the security implications of the system, such as the potential for SQL injection attacks, cross-site scripting attacks, or unauthorized access. Create test scenarios to confirm that the system is safe and capable of withstanding such attacks.
5. Consider previous known issues: Take into account any problems that the module or application has had in the past. Use this knowledge to design test cases that validate that the system can handle similar situations.

Format of negative test cases

The format of negative test cases can vary depending on the testing methodology, the level of detail required, and the individual needs of a project.

Most negative test cases typically include the following elements:

1. Test case ID: A distinct identifier for the test case, usually in the form of a number or text.
2. Test case description: A clear and concise description of the test case that includes the aim and objective of the test.
3. Test data: The invalid inputs, conditions, or events that will be used as test data. Both the inputs to be provided and any pertinent setup or environment details should be included in this.
4. Expected result: A clear and concise description of the expected outcome of the test, including any error messages or responses that should be generated by the system.
5. Actual result: The test’s actual outcome, including any system-generated error messages or responses.
6. Pass/Fail status: A comparison of the expected and actual results that will reveal whether the test was successful or unsuccessful
7. Additional information: Any other details or notes, including any assumptions or constraints, that may be pertinent to the test.

You can use this format to document the negative test cases, helping you comprehend the objectives of each test and keep track of the outcomes. You can customize the format to meet the specific needs of a project, such as by adding additional elements. The key is to ensure that the negative test cases are well-documented and clearly convey the goals and expected outcomes of each test.

Negative Testing Techniques

We need different testing approaches for negative testing to ensure that a comprehensive set of test cases is executed. Here are the techniques that will help you handle unexpected inputs:

1. Input validation testing

Input validation testing focuses on testing the ability of a system to validate user input. The goal is to verify that the software can handle invalid inputs in an appropriate manner, such as by rejecting the input or providing an error message.

For example, consider a system that allows users to enter their names. The system should validate the name to ensure that it only contains valid characters, such as letters and spaces. Designing test cases for input validation testing involves verifying the system’s response to incorrect input, such as a name containing numbers or special characters, to make sure the system rejects the input and displays the proper error message.

By testing the system’s ability to validate input, input validation testing helps to prevent errors and improve the overall quality of the software.

• Boundary value testing

Boundary Value Testing focuses on testing the behavior of the system at the edges of the input domain, where it is most likely to experience problems. The test cases are designed to test the behavior of the system with inputs that are just above and just below the limits of its normal operating range.

For example, in a system that accepts integers as input, the limits of the input domain might be 0 and 100.

Test cases are designed to test the behavior of the system with inputs just above 0 (example, 1) and just below 100 (example, 99).

Boundary value testing is a useful technique for negative testing because it helps to identify problems with the system’s handling of invalid or unexpected input.

• Exception handling testing

This technique involves testing the software’s behavior when unexpected events or exceptions occur. The software will be tested to make sure it can respond to these occurrences and that it won’t crash or act in an unexpected way.

Take a system where users can enter their age as an example. Whenever a user inputs a negative figure for their age, the system should be able to raise an exception to let the user know that the entered value is invalid, and it must then display the relevant error message to the user.

Exception handling testing involves designing test cases to test the behavior of the system when presented with invalid input, such as a negative number for age, to ensure that the system raises the appropriate exception and handles it correctly.

• Exploratory testing

Exploratory testing involves learning by discovery where you can uncover existing potential defects and new unexpected negative scenarios by ad-hoc, unscripted testing and discovery-based manner.

Unlike structured testing techniques, exploratory testing is less focused on pre-determined test cases. In the context of negative testing, exploratory testing can be useful for identifying negative scenarios that may not have been considered in the test plan, such as unexpected interactions between different components of the software or unusual user behaviors.

Think about creating an online store as an example. Exploratory testing examines a website as if it were a client, experimenting with different combinations of inputs and outputs to observe how the system responds. What if the client tries to submit inaccurate data on various forms, such as entering characters into a numeric field or an invalid email address? What happens if a customer makes unauthorized attempts to use the website, such as trying to access parts of the site that are not intended for consumer use?

Webomates offers regression testing as a service that is a combination of test cases based testing and exploratory testing. Test cases based testing establishes a baseline and uses a multi-execution channel approach, to reach true pass / true fail, using AI Automation, automation, manual and crowdsource.  Exploratory testing expands the scope of the test to discover potential problems with the system that might not have been anticipated by the development team.

• Equivalence Partitioning

Equivalence partitioning technique divides the input data of a software system into equivalent classes or partitions. It aims to reduce the number of test cases that must be executed while still covering a representative sample of the input domain.

Each partition represents a subset of the input data that is predicted to behave similarly and can be tested using just one test case.

For example, in a system that accepts integers as input:

• One partition could be the set of negative integers
• Another could be the set of positive integers
• Another partition could be the set of zero.

Each test case is then designed to test one of these partitions, and if it passes, it is assumed that the software will behave correctly for all other inputs within the same partition. By testing a representative sample of the input space, equivalence partitioning can help you ensure that the software can handle any type of input that it might encounter in the real world.

Negative Testing with Webomates

The importance of negative testing cannot be overstated, as it can help identify potential vulnerabilities and weaknesses in the software that could lead to serious issues if left unchecked.

When it comes to selecting a company for negative testing, there are a number of factors to consider, including the company’s experience, expertise, and resources. However, Webomates stands out as an ideal choice for any application’s end-to-end testing.

Customer loyalty is fueled by seamless, personalized experiences. That’s what Webomates helps you achieve. With its unique Testing-as-a-service, Webomates assists you in accomplishing speed, scalability, and predictability.

• The faster you test, the faster you can release! Compared to traditional testing methods, AI-based software testing speeds up product releases and generates the promised business value.

• We have extensive experience and knowledge in identifying vulnerabilities and weaknesses in software. This expertise is essential when it comes to identifying potential issues during negative testing, as it enables you to thoroughly evaluate the software for any potential flaws that could be exploited by malicious actors.

• Webomates uses intelligent automation to help developers work efficiently and effectively. What takes others a week, Webomates can give you results within 24 hours for a full feature test and 8 hours for a module test with healed test cases. In order to dynamically adapt their testing scope to the changes, Webomates utilises AI and ML techniques to predict and self-heal. Such real-time resolutions save a tremendous amount of engineers’ time.

• Our team of highly skilled and experienced testers is trained in identifying potential security vulnerabilities and weaknesses in software. We have a thorough awareness of the most recent risks and attack techniques that hackers frequently employ. This understanding enables us to design negative testing scenarios that accurately simulate real-world attack scenarios, allowing the software to be tested under conditions that closely resemble those encountered in the real world.

With a perfect blend of Agile, DevOps, patented AI Defect Predictor tool and a test automation framework, Webomates ensures that your software is thoroughly tested and able to withstand even the most challenging scenarios.

Be rest assured – hassle-free release is always possible when you partner with Webomates! So sit back and code, and leave the testing to us!

Click here to schedule a demo. You can also reach out to us at info@webomates.com.

Tags: AI Testing, negative testing, Regression Testing, Software Testing, Test Automation