Negative Testing vs Positive Testing – Top Key Differences

Software testing is the process of evaluating and confirming a software program to ensure it functions as intended. It is designed to ensure that a program works as intended and to discover flaws before it is used. There are two main methods for testing software,- Negative and Positive Testing.

In this article, we will clearly distinguish between these two tests with examples to help you write good test cases for your software programs.

Difference Between Negative and Positive Testing

Positive testing ensures that software performs as it is expected to. When writing test cases for positive testing, only legitimate (valid) inputs are provided as inputs. 

In Negative testing, a software program is evaluated against false or incorrect data. This testing is also known as error path testing or failure.

Read More on Negative Testing

Negative vs Positive Testing – Examples of Test Scenarios

Let’s test a software program with a Password text box field allowing users to enter passwords between 8 and 15 alphanumeric characters.

See the table below for various test scenario examples.

Positive Test Scenarios	Negative Test Scenarios
The Password text box should allow 8 characters of input.	The Password text box should throw an error or should not be accepted when less than 8 characters are entered.
The Password text box should allow 15 characters of input.	The password text box should throw an error or should not be accepted when more than 15 characters are entered.
Any values between 8 and 15 characters long should be accepted by the Password text box.	The password text box should not accept special characters as input
It should accept any combination of letters and numbers in the Password text box.	The password text box should not accept a combination of numbers only or a combination of letters only.

Negative vs Positive Testing

In this session, let us discuss some key differences.
 

Positive Testing	Negative Testing
This testing examines a software program’s response with the help of a valid input data set.	This testing means checking the software program’s response using the invalid/incorrect input data set.
Positive testing is not a guarantee of high-quality software.	It ensures that the software product is of high quality.
Positive testing is executed quickly.	It takes more time to execute compared to positive testing.
Positive testing is used consistently to validate the set of test cases that are currently available.	It is used consistently to break the software program (product) with an unidentified set of test cases we will use.
Positive testing’s primary goal is to ensure that the software application consistently complies with the developer’s software requirements specifications (SRS)	This testing’s primary goal is to evaluate a software program’s consistency in the face of erroneous validation data sets.
Positive testing does not cover all possible scenarios.	It encompasses all possible scenarios.
It is a process where the program is validated against a reliable input data set.	It is a process where the program is validated against the invalid input data set.
Positive testing has less impact comparatively.	It is more crucial and significant than Positive testing.
Positive testing can be implemented on all kinds of applications.	It can also be performed on all kinds of applications.
Someone with less knowledge can carry out the positive testing.	Professional software testers mainly use this testing.
It makes sure that the software program meets the required standard.	It makes sure the software works even if it meets unexpected situations.
Positive testing is implemented only for the predicted conditions.	It ensures that the software works for conditions that are tough predict but can happen in real life.

These two tests are two opposing test methods—as the name suggests—but they are also very effective at producing high-quality and bug-free software in the end.

Positive Testing vs Negative Testing- Similarities

Both are important parts of a whole software examination. Even though they have different priorities, both are similar in some major aspects and should be done together to make strong and easy-to-use software at the end. 

Let’s take a look at these two testing techniques and see where they meet.

Commonalities:

Purpose: Both negative as well as positive testing share the same goal — to catch defects, ensuring better quality of the software system.

Life Cycle Integration is possible for them to be integrated throughout the software development life cycle (SDLC), from early requirement stages to post-release maintenance.

Documentation: Both require clear documentation of test cases, expected results and identified bugs.

Test Case Design: Both involve designing test cases with specific inputs and expected outcomes.

Positive Testing (Happy Path Testing) emphasizes the verification that the software functions as intended under normal conditions with valid inputs.

There is a difference between doing negative and positive testing, which are based on the idea that they supply invalid or unexpected inputs deliberately. This helps identify any error, crash or security issues that would occur as a result. 

You can read details on negative testing

The approach to testing is the following:

Testing boundary values (for example, in a field expecting a small integer, you are expected to put down a very large number), invalid data formats and situations of error, which is not described explicitly in documentation requirements. For example, test that inputting special characters or overreaching character limit in a username field brings about an error and check if the application handles it properly.

Balancing Negative with Positive Testing: 

In the context of the project phase and risk assessment, both strategies hold value — though the weightage accorded to each can differ. For instance, during the early stages positive testing might take precedence as a means of confirming core functionality. 

However, as development evolves, negative testing gains more importance: it helps unearth those elusive edge cases which may pose security threats later down the line.

Additional Resources:

This blog post from Testsigma provides a more detailed explanation of negative testing and its various techniques.

Read More – The Different Software Testing Types Explained

Conclusion

Negative and Positive testing go hand in hand and yet when used effectively, both methods can enhance software quality to a great extent. 

It is important for testers to be aware of the advantages and limitations of both approaches so that they are able to develop a thorough testing strategy that ensures user satisfaction throughout the use of the product as well as a strong final output from development.