1 Testing Levels

Testing levels are the stages of testing that correspond to the levels of abstraction and complexity of the software. The main testing levels are unit testing, integration testing, system testing, and acceptance testing. Unit testing verifies the functionality and correctness of individual components or modules of the software. Integration testing checks the compatibility and interaction of the components or modules that are integrated to form a subsystem or a system. System testing validates the performance, reliability, security, and usability of the whole system. Acceptance testing confirms that the system meets the expectations and needs of the end users and the clients.

2 Testing Techniques

Testing techniques are the methods or approaches used to design and execute test cases. The main testing techniques are black-box testing, white-box testing, and gray-box testing. Black-box testing focuses on the input and output of the software without knowing its internal structure or logic. White-box testing examines the internal structure or logic of the software by using code analysis, debugging, or code coverage tools. Gray-box testing combines both black-box and white-box techniques by using some knowledge of the internal structure or logic of the software along with the input and output.

3 Testing Tools

Testing tools are the software applications or libraries that help automate, simplify, or improve the testing process. Testing tools can be classified into different categories based on their functions, such as test management tools, test design tools, test execution tools, test data generation tools, test reporting tools, test debugging tools, test performance tools, and test security tools. Some examples of testing tools are JUnit, Selenium, TestNG, Cucumber, JMeter, Postman, SonarQube, and OWASP ZAP.

4 Testing Standards

Testing standards are the guidelines or best practices that define the quality criteria, processes, and procedures for testing. Testing standards help ensure consistency, accuracy, completeness, and efficiency of testing. Testing standards can be derived from various sources, such as industry standards, organizational standards, project standards, or regulatory standards. Some examples of testing standards are IEEE 829, ISO/IEC 29119, ISTQB, and CMMI.

5 Testing in SDLC Phases

Testing is an integrated and aligned activity throughout the Software Development Life Cycle (SDLC), from planning to maintenance. During the planning phase, testing objectives, scope, strategy, plan, and schedule are defined. Resources, roles, and responsibilities are identified. Standards, criteria, and metrics are established. The analysis phase involves analyzing the requirements and specifications of the software to identify testable features and functions. Designing test cases and scenarios based on the testing techniques and levels is also done. In the design phase, the design of the software is reviewed and refined to verify the feasibility and compatibility of the test cases and scenarios. The testing tools and environment are also selected and configured. During development, code is implemented and documented with unit testing and code analysis being done to fix and report defects or bugs. Testing involves executing test cases and scenarios with integration, system, and acceptance testing being done. Results are recorded and analyzed with defects or bugs being reported and tracked. Deployment of software to production environment includes installation testing, configuration testing, compatibility testing as well as performance, reliability, security, and usability monitoring/evaluation. Maintenance includes support/updates for software with regression testing, retesting, change impact analysis being done as well as enhancements/modifications/patches implementation/testing. To deliver high-quality software that meets stakeholders' expectations/needs, appropriate standards for each SDLC phase must be followed in terms of testing levels/techniques/tools/standards.