The main objectives of software testing are to check and validate that the software product works as intended and to enhance the software’s quality. The two major types of software testing are functional and non-functional testing. Positive and negative testing go under functional testing.
These testing approaches have their main features and functionalities and play a significant role in testing the software product. This article will cover the basics and explore the differences between the two while offering examples.
First of all, to test any application, we need to provide input values to validate if the results are based on the given requirements or not.
In positive and negative testing, the following elements must be considered:
- Input data
- An action that needs to be performed
- Output data
What is positive testing?
Positive testing is a type of testing performed by a software application that provides valid input data sets.
This type of testing determines whether your application behaves as expected with positive inputs or not. If an error is encountered during positive testing, the test fails.
Example: In an app, there is a text box that can only accept digits. The system will receive values up to 99999; any other numbers should not be accepted. For positive testing, set the valid input values from 0 to 99999 and see if the system accepts the inputs.
What is negative testing?
Negative testing evaluates whether your software can handle invalid input or unexpected user behavior.
It ensures that the product does not collapse and stays stable in the presence of incorrect data inputs.
Example: Negative tests can be carried out by inputting characters ranging from A to Z or from a to Z. Either way, the software system must reject the values or provide an error in response to these data inputs.
Here are some testing techniques used for positive and negative testing:
Boundary Value Analysis
It is a software testing methodology where test cases are designed with boundary values in a range.
Example: A system can accept numeric values ranging from 0 to 10. All other digits are invalid values. The boundary values -1,0,1 and 9,10,11 will be tested using this methodology.
This software testing methodology divides input data into multiple partitions. Each partition’s values must be tested at least once. Positive testing uses partitions with valid values. Negative testing is achieved on partitions with invalid values.
Example: The numbers from 0 to 10 can be divided into two or three partitions. We have two divisions in our case: -10 to -1 and 0 to 10. Sample values (5 and -5) may be taken from each situation to test the scenarios.
The Yin and Yang: Benefits and Importance
- Comprehensive Coverage: While positive testing often misses edge cases, negative testing ensures that all possibilities are explored, giving you a well-rounded quality assurance process.
- Cost-Effectiveness: Uncovering bugs earlier in the development phase through focused testing is a lot cheaper than dealing with issues once the product is live.
Consider an e-commerce platform where a bug allowed users to enter negative values for product quantities, leading to skewed inventory data. A balanced approach of positive and negative testing could’ve prevented this real-life blunder, safeguarding both the user experience and the company’s bottom line.
Limitations to Keep in Mind
Understanding the limitations of positive and negative testing is key to developing a balanced, efficient QA strategy. Here’s what you should watch out for:
Limitations of Positive Testing
- False Sense of Security: Positive testing mainly deals with ‘happy path’ scenarios, meaning it only checks if the program works under ideal conditions. This can provide a deceptive sense of assurance that the software is bug-free.
- Scope Limitation: Positive testing doesn’t cover edge cases or unexpected user behavior. This limitation leaves gaps in your testing strategy where bugs can hide.
- Lack of Robustness: Solely relying on positive tests might result in a product that appears stable under ‘lab conditions’ but breaks when confronted with real-world anomalies.
Limitations of Negative Testing
- Resource Intensive: Negative testing tries to cover all the bases, which requires a substantial investment in time and skilled manpower. Because it’s comprehensive, it can often seem like you’re looking for a needle in a haystack.
- Complexity: Negative testing often involves complex test cases that are difficult to design and maintain. If not well-documented, this complexity can become a hindrance in future test cycles.
- Risk of Overemphasis: It’s easy to go overboard with negative tests, especially when it’s known that the software will be used in highly variable conditions. The downside is that too much focus on negative testing can lead to a negligence of positive scenarios, causing an imbalance in your testing strategy.
- False Positives: When exploring the full range of ‘what could go wrong,’ negative testing could generate false positives that may not represent actual defects but consume resources to investigate.
Differences between positive and negative testing:
|does not cover all possible cases.
|It covers all possible cases.
|It’s implemented only for expected conditions.
|It’s implemented for unexpected conditions.
|It’s performed on every application.
|It’s performed where there are chances of unexpected conditions.
|Execution time is shorter for positive testing.
|Execution time is longer for negative testing.
|It’s a testing process where the system is validated in contradiction to the valid input data.
|It’s a testing process that contains validation in contrast to invalid input data.
|Inexperienced people can execute it.
|Testing professionals can perform it.
|Positive testing is less significant than negative testing.
|Negative testing is more vital than positive testing.
|It ensures software is standard.
|It provides 100% defect-free software.
After comparing the two types of testing, we can conclude that software testing can help deliver quality software products and ensure bug-free software before its launch. Both positive and negative testing help verify that the software product works as expected. Real-time users can enter any value that must be checked before the launch.
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