The Methods of Software Testing
As we mentioned earlier, the main goal of software testing is to reduce the presence of errors in ready software solutions so they can be safely delivered to end users. Each part of the software requires different testing approaches to ensure the complete software meets quality standards.
However, the truth is that no software is 100% bug-free. Moreover, it cannot be fully tested due to the infinite number of possible inputs, configurations, and scenarios that users might encounter.
Therefore, QA engineers use different methods to identify the best test cases depending on specified conditions. Let’s take a closer look at these methods:
Black-box testing
This method examines the software’s functionality without delving into its internal code structure. Testers treat the software as a “black box” (hence the name), where they input various data sets and observe the outputs to ensure they align with expected results.
Black box testing is precious for validating user interactions, input validations, and overall system behavior. It ensures that the software performs correctly from an end-user perspective, regardless of how it’s implemented internally.
- Functional, performance, use case, and usability testing.
White box testing
Contrary to the black box method, this technique involves in-depth knowledge of the code, which is why, most often, it’s executed either by developers or software architects. They examine the code, algorithms, and system architecture to identify potential flaws and vulnerabilities and ensure that all code paths are properly executed.
- Unit and security testing.
Gray box testing
As it comes from the name, gray box testing combines elements of both black box and white box techniques. Testers are expected to have partial knowledge of the software’s internal structure, allowing them to design test cases that consider the application’s functional and structural aspects.
- Integration and security testing.
Ad hoc testing
Ad hoc is a flexible and spontaneous approach. It doesn’t follow predefined test cases or scripts. Test engineers, often with a good understanding of the application and domain, explore the software freely, trying different actions and inputs based on their intuition and experience. This method is especially useful for uncovering unexpected issues, irregular behaviors, and disability problems that formal test cases may not cover.
- Usability and exploratory testing, quick checks for critical issues.
Regression testing
This is an iterative method aimed at ensuring that new code changes or updates do not introduce new defects or disrupt existing functionality. Test cases from previous cycles are re-executed to verify that the software still operates correctly after modifications. Regression testing can be applied to all testing types and levels and is often automated to minimize time, effort, and labor costs.
Seven Principles of Software Testing
Before wrapping up, let’s touch upon the principles of software testing that every QA professional should know and apply to ensure effective and reliable outcomes. These seven principles are described in the book “Foundations for Software Testing” by Dorothy Graham, Erik Van Veenendaal, and Isabel Evans and serve as guiding rules.
#1. Testing reveals the presence of mistakes
First and foremost, it’s essential to understand that testing doesn’t insure against mistakes. As we’ve mentioned earlier, there’s no 100% bug-free software, and the whole idea of testing is to ensure that the number of these issues is reduced to a minimum.
#2. It’s not possible to perform exhausting testing
Secondly, it’s impossible to test all the potential test cases and scenarios that may arise in an application. To give you the gist, a simple form with 5 input fields and two options would require creating 32 test cases to cover all combinations.
Now imagine more complex software with numerous features and value options. To fully test this software, teams must spend weeks creating every possible scenario and input, which is impractical and costly. Therefore, instead of wasting time and resources on a task that’s impossible, organizations focus on the most critical areas of software where defects are most likely to occur.
#3. Test early
As we stated earlier, the cost of fixing a bug increases exponentially throughout the software development life cycle, so it’s important to involve professional teams as early in the development process as possible. By working in parallel with the development team, test engineers can quickly identify defects and bugs and ensure they don’t add up and destroy the logic of the entire product.
#4. Defect clustering
Defect clustering is based on the Pareto principle, which says that 80% of bugs and defects are typically found in 20% of system modules. This way, if a bug is found in one of the modules, chances are high that there are more issues hidden from view.
#5. Pesticide paradox
The Pesticide paradox principle emphasizes the need for continuously updating and evolving test cases. It recognizes that as a software product evolves, the same set of test cases, if repeatedly used, may become less effective at finding defects. Therefore, it’s necessary to regularly review test strategies and introduce new test scenarios, data inputs, and techniques to keep pace with the changing software.
#6. Testing is context dependent
This principle means that testing different types of software applications will require different approaches, techniques, and methodologies. For instance, safety measures that are highly important for fintech applications have a lower priority for corporate websites. Similarly, you’ll need to use different approaches when testing an e-commerce application.
#7. Absence of errors fallacy
If the software is free from bugs, this isn’t always an indicator of proper quality. It can very well be that it’s been tested for the wrong requirement. Of course, the primary goal of software QA and QC is to minimize the amount of defects, but more than anything else, it is also to ensure that the software product meets the user’s needs and expectations.
What’s Trending for 2024-2025 in Software Testing
We see the following trends for software testing and QA for 2024-2025. The focus is on practical, tech-driven advancements that are becoming essential for teams working on modern software projects:
AI-powered testing
AI is being used to automatically generate realistic test data sets and beyond. This helps improve test coverage and reduces the manual effort needed for preparing data. Teams can now simulate real-world data scenarios more efficiently.
Identify areas where AI can add value (e.g., regression, test data generation). Evaluate AI-powered tools that align with your tech stack. Ensure that AI-driven tests cover both functional and non-functional testing. | Set up feedback loops to improve AI model performance. Regularly validate AI-generated test cases against real-world scenarios. Monitor AI models for bias or overfitting in test case generation. |
Chaos engineering in QA
Intentionally introducing failures to see how systems respond is gaining traction. Known as chaos engineering, this approach is helping teams build more resilient cloud-native systems by exposing weak points in a controlled way.
Define system performance expectations under failure conditions. Identify key components of the system to introduce controlled failures. Set up monitoring to capture metrics before and after chaos experiments. | Use tools like Gremlin or Chaos Monkey to simulate failures. Analyze system behavior and apply learnings to strengthen fault tolerance. Schedule regular chaos experiments as part of the release cycle. |
API security testing
As APIs become central to modern apps, API security testing is increasingly important. Techniques like fuzzing and penetration testing specifically target APIs to ensure secure and reliable interactions between services.
Automate fuzz testing to explore unexpected inputs and attack vectors. Use tools like OWASP ZAP or Burp Suite for real-time API vulnerability scanning. Ensure token validation and rate limiting are part of your security tests. | Run penetration tests focusing on authentication and authorization flows. Test for SQL injection, XSS, and CSRF vulnerabilities. Monitor API logs for anomalies that could indicate potential security threats. |
Shift-right testing and observability
Extending testing into production environments is now common. By using observability tools, teams can monitor and detect issues in real-time, allowing for faster diagnosis and resolution while software is live.
Set up automated alerting for critical production issues. Implement real-time monitoring with tools like Prometheus, Datadog, or New Relic to capture system performance. Use distributed tracing (e.g., Jaeger, OpenTelemetry) to track requests and troubleshoot issues across microservices. | Run canary releases to test features on a small percentage of users before full rollout. Monitor user behavior and errors in production using synthetic monitoring tools like Catchpoint. Capture metrics and logs from production environments to drive continuous improvements. |
Blockchain testing frameworks
With the rise of blockchain, there are new frameworks designed for testing smart contracts and decentralized systems. These tools help ensure blockchain apps run smoothly and securely.
Use blockchain-specific testing tools like Truffle or Hardhat to test smart contracts. Perform gas optimization testing to ensure your smart contracts are cost-efficient. Test for security vulnerabilities in smart contracts (e.g., reentrancy, integer overflows). | Use mock testing environments to simulate different blockchain network states. Validate cross-chain compatibility if the app interacts with multiple blockchains. Ensure smart contracts meet regulatory compliance standards like GDPR or financial regulations. |
AI model testing and validation
AI/ML models require specialized testing. Teams are developing methods to test for bias, explainability, and performance across various data sets, ensuring AI systems are reliable and fair.
Test for model bias by evaluating performance across diverse data sets (gender, race, age, etc.). Use explainability tools like LIME or SHAP to ensure model decisions can be interpreted by humans. Perform adversarial testing to evaluate how the model handles malicious input data. | Continuously validate the model with real-time data to avoid model drift. Test model performance under various conditions (e.g., different data distribution, noise). Ensure compliance with ethical AI standards and regulatory requirements like GDPR. |
Low-code/No-code testing tools
Visual testing tools are on the rise, allowing non-technical team members to contribute to the QA process. These tools simplify test creation, helping cross-functional teams work more efficiently.
Evaluate tools like Virtuoso for compatibility with your team’s current workflows. Ensure that test scripts created with visual tools are version-controlled and trackable. Allow non-technical team members to create simple test scenarios. Test low-code/no-code tools for cross-platform compatibility. | Integrate the low-code testing tool into CI/CD pipelines to ensure continuous feedback Implement reusable test modules to improve the creation of repetitive test scenarios. Ensure low-code tools can handle data-driven testing, especially for dynamic test cases. Use AI-driven suggestions within no-code platforms to auto-generate optimized test steps. |
Performance testing for 5G applications
With the expansion of 5G, testing for ultra-low latency and high-bandwidth use cases is crucial. Performance testing is adapting to meet the demands of this next-generation network infrastructure.
Simulate network latency and high-bandwidth conditions in testing. Test for device handoff between 5G cells. Measure throughput and packet loss during high-traffic scenarios. | Validate the app’s behavior under ultra-low latency conditions. Ensure the app handles multiple concurrent connections effectively. Monitor performance for real-time applications like streaming and gaming. |