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Always turn a negative situation into a positive situation.
This is an excellent advice from Michael Jordan. However, we explicitly create negative testing scenarios in software testing to enhance the product quality remarkably. This article elaborates on what positive and negative testing are. Also, we will look into their scenarios, differences, examples, and best practices.
Let us go!
What is Positive and Negative Testing?
Positive Testing: Also known as “Happy Path Testing”. It is an approach that executes test cases in normal conditions. It focuses on the application performing as intended according to its specifications when valid inputs are entered.
Example: For a web application you need to positive test a form submission. Fill out all the required fields correctly as per the specifications and then submit the form. The expected result is that the form is successfully submitted, and the confirmation message is displayed. The test case is marked as passed if these expected results are achieved. This whole process marks the successful completion of positive scenario testing.
Negative Testing: Also known as “Error Path Testing” or “Failure Testing”. It is an approach that executes test cases in unexpected and extreme conditions. It focuses on how gracefully the application performs when invalid inputs are entered.
Example: For the same web application, you need to negative test the form submission. Fill out invalid inputs in the fields such as alphabets in the ‘Telephone No.’ field. Try to submit the form without providing all the required fields. The expected result is that the relevant error message is displayed, and the form is not submitted successfully. The test case is marked as passed if these expected results are achieved.
A Use Case of Positive and Negative Testing
Consider a use case when you are using an ATM (Automated Teller Machine) to withdraw money.
Positive Testing Scenario
Below are the test steps that should be followed for a positive testing test case:
Test Steps
- Go to the ATM
- Insert your card and correctly enter your PIN.
- Select the withdrawal option.
- Choose a valid amount within your account’s balance and the ATM’s dispensing limit.
Expected Result: The ATM processes your request and dispenses the correct amount. Finally, it prints a receipt for the transaction.
Actual Result: As per the expectations.
Negative Testing Scenario
Below are the test steps that should be followed for a negative testing test case:
Test Steps
- Go to the ATM
- Insert your card and enter an incorrect ATM PIN.
Expected Result: The ATM displays an error message: “Incorrect PIN”. It gives you three additional attempts before blocking the card and denying any further attempts.
Actual Result: As per the expectations.
In these examples, positive testing checks if the ATM works correctly under normal and ideal conditions (correct card, PIN, withdrawal request, etc.). Negative testing works with the ATM’s response to incorrect situations (such as a wrong PIN). It checks that the system is secure against potential security issues or errors.
Positive Testing vs. Negative Testing
| Insight | Positive Testing | Negative Testing |
|---|---|---|
| Definition | Testing with the intention that the system will work as expected under normal conditions and input. | Testing with the intention that the system can handle invalid and extreme conditions gracefully. |
| Objective | The system works as intended with valid inputs and conditions. | The system does not behave unpredictably under invalid inputs and conditions. |
| Input Type | Valid and expected. | Invalid, unexpected, and extreme. |
| Outcome | Successful execution of application’s functions. | Proper handling of errors (through appropriate messages) without crashing. |
| Error Handling | Not a primary focus. | Error handling is the main focus. |
| Example: | Test a login feature by entering valid username and password combinations. The expected result is successful authentication and access to the user’s dashboard. |
Entering incorrect usernames and passwords to check if the system properly denies access and displays appropriate error messages. |
| Interpretation | A successful test (Passed) confirms that the system’s functionality works as expected. | A successful test (Passed) confirms that the system’s ability to handle errors and unexpected inputs is working as expected. |
| Importance in QA | It is essential to perform basic testing to cover predictable scenarios. | It is essential to perform robust testing to cover unpredictable scenarios and provide better coverage to deliver quality products. |
Best Practices for Positive and Negative Testing
Here are a few general best practices that apply to positive and negative testing scenarios:
- Build a Comprehensive Test Plan: Develop a detailed plan covering positive and negative test scenarios. Here is a guide to building a test plan.
- Continuous Improvement: Gather the feedback from testing and imbibe that into the development cycle.
- Team Collaboration: A team that works together goes farther. Communication and collaboration between developers, testers, and other stakeholders are essential.
- Updated and Maintained Tests: Keep the test scripts updated to reflect changes in the application(UI, functional changes) and user requirements.
Best Practices for Positive Testing
- Understand the Requirements Thoroughly: The application’s functional requirements should be properly understood first to create good test scenarios.
- Create Valid Test Cases: Design test cases that match the expected inputs, where the system provides the expected output as intended.
- Use Priority in User Scenarios: Focus on common and critical user flows that are most likely to be used by actual users.
- Data Driven Testing: Use varied and valid input data to test different scenarios. Read here how to adopt data-driven testing to bring your QA to the next level.
- Check for Expected Outcomes: The system should perform as expected and produce the correct output for the given inputs.
- Regression Testing: Perform regression tests whenever there are new code changes so that the new code does not affect existing working functionalities.
- Automate and Automate: Use automation for repetitive and high-volume tests to increase efficiency. Here are the top 7 automation testing tools to consider.
Best Practices for Negative Testing
- Identify Invalid Inputs: Identify the inputs that the system should not accept or handle. Examples are out-of-range values, incorrect data types, or extreme inputs designed to cause failures.
- Test Error Handling: The system should gracefully handle invalid inputs. It should provide proper and informative error messages without crashing or behaving unpredictably.
- Boundary Value Analysis (BVA): Focus on edge cases and boundary conditions, which help catch bugs to a greater degree.
- Security Tests: Include security tests for vulnerabilities, such as SQL injection, buffer overflows, other malicious attacks, etc.
- Stress Testing: Check system stability and performance under unexpected or stressful conditions.
- Use Negative Data Sets: Use a broad range of invalid, unexpected, or random data inputs to test system responses through negative datasets.
Conclusion
You require both positive and negative testing to build great quality into your product. You can not just rely on any one of them during the product testing activities. This two-way approach helps you test the functionality correctly through positive testing. Then, find any hidden bugs through negative testing.
Choosing an intelligent automation testing tool to achieve these goals can significantly improve your application’s delivery time, quality, and test coverage. testRigor is a generative AI-based test automation tool that lets you write test cases in plain English. Using testRigor, everyone in your team can write and execute test cases irrespective of their technical proficiency. See here the top features of testRigor.
