Software Engineering Basic Testing Work for Beginners
- 2. SoftwareTesting Fundamentals • Software testing can be stated as the process of verifying and validating whether a software or application is bug-free, meets the technical requirements as guided by its design and development, and meets the user requirements effectively and efficiently by handling all the exceptional and boundary cases. • The process of software testing aims not only at finding faults in the existing software but also at finding measures to improve the software in terms of efficiency, accuracy, and usability. It mainly aims at measuring the specification, functionality, and performance of a software program or application. Kanyapur Polytechnic 2
- 3. Continued… • Software testing can be divided into two steps: ➢ Verification: it refers to the set of tasks that ensure that the software correctly implements a specific function. ➢ Validation: it refers to a different set of tasks that ensure that the software that has been built is traceable to customer requirements. Verification: “Are we building the product right?” Validation: “Are we building the right product?” Kanyapur Polytechnic 3
- 4. A Strategic Approach to SoftwareTesting • Any Testing Strategy should have the following characteristics: ➢ Use of effective technical reviews ➢ Should begin at the component level and cover the entire system ➢ Different testing techniques are appropriate for different software engineering approaches and at different points in time ➢ Testing is conducted by the developer of the software and an independent test group ➢ Debugging must be accommodated in any testing strategy Kanyapur Polytechnic 4
- 5. DifferentTypes of SoftwareTesting • Manual Testing - Testing software manually, i.e., without using any automation tool or any script - The tester takes over the role of an end-user and tests the software to identify any unexpected behavior or bug • Automatic Testing - also known as Test Automation - It is the process of transforming the manual test cases into test scripts with the help of automation technologies or any programming language - It is used to re-run the test scenarios quickly and repeatedly, that were performed manually in manual testing - As compared to manual testing, it increases the test coverage, improves accuracy, and saves time and money Kanyapur Polytechnic 5
- 6. Different types of SoftwareTestingTechniques • Black Box Testing: - The technique of testing in which the tester doesn’t have access to the source code of the software and is conducted at the software interface without any concern with the internal logical structure of the software • White Box Testing: - The technique of testing in which the tester is aware of the internal workings of the product, has access to its source code, and is conducted by making sure that all internal operations are performed according to the requirement specifications Kanyapur Polytechnic 6
- 7. Continued… Black Box Testing White BoxTesting An application's internal workings are not necessary Knowledge of the internal workings is a must Also known as closed box/data-driven testing Also known as structural testing or clear box testing Performed by end users, testers, and programmers Typically performed by testers and developers This can only be accomplished by trial and error Data domains and internal bounds can be tested more thoroughly Kanyapur Polytechnic 7
- 8. Testing Strategies for Conventional Software • Unit Testing - individual units/components of a software/system are tested - The purpose is to validate that each unit of the software performs as designed - It focuses on the internal processing logic and data structures within the boundaries of a component. - This type of testing can be conducted in parallel for multiple components • Integration Testing - individual units are combined and tested as a group - The purpose of this level of testing is to expose faults in the interaction between integrated units - It focuses on the design and construction of the software architecture Kanyapur Polytechnic 8
- 9. Continued… • Regression Testing - It is the re-execution of some subset of tests that have already been conducted to ensure that changes have not propagated unintended side effects - Regression testing may be conducted manually, by re-executing a subset of all test cases or using automated capture/playback tools • Smoke Testing - It is an integration testing approach that is commonly used when product software is developed - Smoke testing is performed by developers before releasing the build to the testing team and after releasing the build to the testing team it is performed by testers whether to accept the build for further testing or not - It is designed as a pacing (Speedy) mechanism for time-critical projects, allowing the software team to assess the project on a frequent basis Kanyapur Polytechnic 9
- 10. ValidationTesting ❑ Through Validation testing, requirements are validated against the software constructed. These are high-order tests where validation criteria must be evaluated to assure that software meets all functional, behavioral and performance requirements. It succeeds when the software functions in a manner that can be reasonably expected by the customer. Kanyapur Polytechnic 10
- 11. Validation testing using Alpha & Beta Testing • Alpha Testing: - A type of acceptance testing which is performed to identify all possible bugs/issues before releasing the product to the end-user - It is a preliminary software field test carried out by a team of users to find out the bugs that were not found previously by other tests - It simulates a real user environment by carrying out tasks and operations that actual user might perform • Beta Testing: - A type of acceptance testing which is the final test before shipping a product to the customers - It is implemented by "real users "of the software application in a "real environment." The software is released to a limited number of end-users of the product to obtain feedback on the product quality. - It reduces product failure risks and increases the quality of the product through customer validation. - Direct feedback from customers is a significant advantage of beta testing which helps the developers to make final changes before releasing the software product. Kanyapur Polytechnic 11
- 12. Continued… Alpha Testing Beta Testing Involves both the white box and black box testing Uses only black box testing Performed by testers who are usually internal employees of the organization Performed by clients who are not part of the organization Performed at the developer’s site Performed by the actual end-users of the product Does not check reliability and security Checks reliability and security Ensures the quality of the product before forwarding to beta testing Ensures that the product is ready for real time users Requires a testing environment or a lab Doesn’t require a testing environment or lab May require a long execution cycle Requires only a few weeks of execution Developers can immediately address the critical issues or fixes Most of the collected issues or feedback are implemented in future versions of the product Multiple test cycles are organized Only one or two test cycles are there Kanyapur Polytechnic 12
- 13. SystemTesting ❑ In system testing, software and other system elements are tested as a whole. Software is combined with other system elements like Hardware, People, Database and the overall functioning is checked by conducting a series of tests. These tests fully exercise the computer based system. Kanyapur Polytechnic 13
- 14. Continued… • Recovery testing: Systems must recover from faults and resume processing within a pre- specified time. It forces the system to fail in a variety of ways and verifies that recovery is properly performed. • Security Testing: This verifies that protection mechanisms built into a system will protect it from improper penetrations. Tester plays the role of hacker. • Stress testing: It executes a system in a manner that demands resources in abnormal quantity, frequency or volume and tests the robustness of the system. • Performance Testing: This is designed to test the run-time performance of the software within the context of an integrated system. They require both hardware and software instrumentation. Kanyapur Polytechnic 14
- 15. Debugging • Debugging is the process of identifying and resolving errors, or bugs, in a software system. It can be a time-consuming and complex task, but it is essential for ensuring that a software system is functioning correctly. • Steps involved in debugging are: - Problem identification and report preparation - Assigning the report to the software engineer to verify that it is genuine - Defect Analysis using modeling, documentation, finding and testing candidate flaws, etc. - Defect Resolution by making required changes to the system - Validation of corrections Kanyapur Polytechnic 15
- 16. Debugging vsTesting Testing Debugging Testing is the process to find bugs and errors. Debugging is the process of correcting the bugs found during testing. It is the process to identify the failure of implemented code. It is the process to give a solution to code failure. Testing is done by the tester. Debugging is done either by the programmer or by the developer. There is no need of design knowledge in the testing process. Debugging can’t be done without proper design knowledge. Testing can be done by insiders as well as outsiders. Debugging is done only by insiders Testing is initiated after the code is written. Debugging commences with the execution of a test case. Kanyapur Polytechnic 16
- 17. Debugging Process Strategies ➢ Brute Force: Study the system for a larger duration in order to understand the system. It helps the debugger to construct different representations of systems to be debugged depending on the need. A study of the system is also done actively to find recent changes made to the software. ➢ Backtracking: Backward analysis of the problem which involves tracing the program backward from the location of the failure message in order to identify the region of faulty code. A detailed study of the region is conducted to find the cause of defects. ➢ Forward analysis of the program involves tracing the program forwards using breakpoints or print statements at different points in the program and studying the results. The region where the wrong outputs are obtained is the region that needs to be focused on to find the defect. ➢ Using past experience with the software to debug the software with similar problems in nature. The success of this approach depends on the expertise of the debugger. ➢ Cause elimination introduces the concept of binary partitioning. Data related to the error occurrence are organized to isolate potential causes. A list of all possible causes is developed and tests are conducted to eliminate each of them Kanyapur Polytechnic 17
- 18. Continued… ➢ Static analysis: Analyzing the code without executing it to identify potential bugs or errors. This approach involves analyzing code syntax, data flow, and control flow. ➢ Dynamic analysis: Executing the code and analyzing its behavior at runtime to identify errors or bugs. This approach involves techniques like runtime debugging and profiling. ➢ Collaborative debugging: Involves multiple developers working together to debug a system. This approach is helpful in situations where multiple modules or components are involved, and the root cause of the error is not clear. ➢ Logging and Tracing: Using logging and tracing tools to identify the sequence of events leading up to the error. This approach involves collecting and analyzing logs and traces generated by the system during its execution. ➢ Automated Debugging: The use of automated tools and techniques to assist in the debugging process. These tools can include static and dynamic analysis tools, as well as tools that use machine learning and artificial intelligence to identify errors and suggest fixes. Kanyapur Polytechnic 18