Software Testing Strategies
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The document outlines software testing strategies, emphasizing the integration of test case design into a systematic approach, which involves test planning, execution, and result evaluation. It distinguishes between conventional software testing and object-oriented testing, detailing specific strategies like unit testing, integration testing, and validation testing for each approach. Key concepts include the differences in testing methods, the focus of testing at various development stages, and the importance of effective documentation and error handling throughout the process.
Software Testing Strategies
- 1. SOFTWARE TESTING STRATEGIES SUBMITTED TO:- SUBMITTED BY:- MR. RAKESH KUMAR ALPANA (171401) ASTT. PROFESSOR ME MODULAR(CSE) COMPUTER SCIENCE & ENGG. E-MAIL:[email protected] NITTTR CHANDIGARH
- 2. CONTENTS •Introduction •A strategic approach to testing •Test strategies for conventional software •Test strategies for object-oriented software •Difference between conventional and object- oriented software testing •Reference
- 3. Introduction • A strategy for software testing integrates the design of software test cases into a well-planned series of steps that result in successful development of the software. • The strategy provides a road map that describes the steps to be taken, when, and how much effort, time, and resources will be required.
- 4. • The strategy incorporates test planning, test case design, test execution, and test result collection and evaluation. • The strategy provides guidance for the practitioner and a set of milestones for the manager .Because of time pressures, progress must be measurable and problems must surface as early as possible.
- 5. A STRATEGIC APPROACH TO TESTING • To perform effective testing, a software team should conduct effective formal technical reviews. • Testing begins at the component level and work outward toward the integration of the entire computer based system. • Different testing techniques are appropriate at different points in time. • Testing is conducted by the developer of the software and (for large projects) by an independent test group. • Testing and debugging are different activities, but debugging must be accommodated in any testing strategy.
- 6. SOFTWARE TESTING STRATEGY • Unit testing – Concentrates on each component/function of the software as implemented in the source code • Integration testing – Focuses on the design and construction of the software architecture • Validation testing – Requirements are validated against the constructed software • System testing – The software and other system elements are tested as a whole
- 8. TEST STRATEGIES FOR CONVENTIONAL SOFTWARE (1) Unit Testing • Focuses testing on the function or software module • Concentrates on the internal processing logic and data structures • Is simplified when a module is designed with high cohesion • Reduces the number of test cases • Allows errors to be more easily predicted and uncovered • Concentrates on critical modules and those with high cyclomatic complexity when testing resources are limited
- 9. TARGETS FOR UNIT TEST CASES • Module interface • Ensure that information flows properly into and out of the module • Local data structures • Ensure that data stored temporarily maintains its integrity during all steps in an algorithm execution • Boundary conditions • Ensure that the module operates properly at boundary values established to limit or restrict processing • Independent paths (basis paths) • Paths are exercised to ensure that all statements in a module have been executed at least once • Error handling paths • Ensure that the algorithms respond correctly to specific error
- 11. DRIVERS AND STUBS FOR UNIT TESTING • Driver • A simple main program that accepts test case data, passes such data to the component being tested, and prints the returned results • Stubs • Serve to replace modules that are subordinate to (called by) the component to be tested • It uses the module’s exact interface, may do minimal data manipulation, provides verification of entry, and returns control to the module undergoing testing • Drivers and stubs both represent overhead • Both must be written but don’t constitute part of the installed software product
- 12. (2) Integration Testing • Defined as a systematic technique for constructing the software architecture • At the same time integration is occurring, conduct tests to uncover errors associated with interfaces • Objective is to take unit tested modules and build a program structure based on the prescribed design • Two Approaches • Non-incremental Integration Testing • Incremental Integration Testing
- 13. NON-INCREMENTAL INTEGRATION TESTING • Commonly called the “Big Bang” approach • All components are combined in advance • The entire program is tested as a whole • Chaos results • Many seemingly-unrelated errors are encountered • Correction is difficult because isolation of causes is complicated • Once a set of errors are corrected, more errors occur, and testing appears to enter an endless loop
- 14. INCREMENTAL INTEGRATION TESTING • Three kinds • Top-down integration • Bottom-up integration • Sandwich integration • The program is constructed and tested in small increments. • Errors are easier to isolate and correct. • Interfaces are more likely to be tested completely. • A systematic test approach is applied.
- 15. OBJECT-ORIENTED TESTING STRATEGIES (1) Unit Testing • Smallest testable unit is the encapsulated class or object • Test each operation as part of a class hierarchy because its class hierarchy defines its context of use • Driven by class operations and state behavior, not algorithmic detail and data flow across module interface • Approach: Test each method (and constructor) within a class Test the state behavior (attributes) of the class between methods
- 16. CONTD… • Complete test coverage of a class involves Testing all operations Setting and interrogating all object attributes Exercising the object in all possible state . • Test sequences are designed to ensure that relevant operations are exercised . • State of the class is examined to determine if errors exist .
- 17. CONTD… • How is class testing different from conventional testing? • Conventional testing focuses on input- process-output, whereas class testing focuses on each method, then designing sequences of methods to exercise states of a class. • But white-box testing can still be applied .
- 18. CONTD… (2) Integration Testing • OO does not have a hierarchical control structure so conventional top- down and bottom-up integration tests have little meaning . • Focuses on groups of classes that collaborate in some manner. • Integration of operations one at a time into a class is often meaningless Because of direct and indirect interaction of components .
- 19. CONTD… • Thread-based testing Testing/integrate the set of classes required to respond to one input or event • Cluster testing Groups of collaborating classes are tested for interaction errors • Regression testing is important as each thread, cluster or subsystem is added to the system
- 20. CONTD… (3)Validation Testing • Are we building the right product? • Validation succeeds when software functions in a manner that can be reasonably expected by the customer. • Focuses on visible user actions and user recognizable outputs • Validation tests are based on the use-case scenarios, the object behavior model, and the event flow diagram
- 21. CONTD… • Apply: • Use-case scenarios from the software requirements spec • Black-box testing to create a deficiency list • Acceptance tests through alpha (at developer’s site) and beta (at customer’s site) testing with actual customers
- 22. CONTD… • Software may be part of a larger system. • This often leads to “finger pointing” by other system dev teams Finger pointing defence: • 1. Design error-handling paths that test external information • 2. Conduct a series of tests that simulate bad data • 3. Record the results of tests to use as evidence
- 23. CONTD… (4)System Testing • Types of System Testing: • Recovery testing: how well and quickly does the system recover from faults. • Security testing: verify that protection mechanisms built into the system will protect from unauthorized access (hackers, disgruntled employees, fraudsters). • Stress testing: place abnormal load on the system . • Performance testing: investigate the run-time performance within the context of an integrated system .
- 24. DIFFERENCE BETWEEN CONVENTIONAL AND OBJECT ORIENTED TESTING Conventional testing • Conventional testing is the traditional approach to testing mostly done when water fall life cycle is used for development. • Conventional testing focuses more on decomposition and functional approaches. Object oriented testing • Object oriented testing is used when object oriented analysis and design is used for developing enterprise software. • Object oriented testing, uses composition.
- 25. Conventional testing • The three levels of testing (system, integration, unit) used in conventional testing. • Traditional development follows a sequential approach. • Needs to large duration sometimes to development the large projects. • Uses common processes likes: analysis, design, implementation, and testing Object oriented testing • not clearly defined when it comes to object oriented testing. • OO development uses incremental approach. • Need to more time than Traditional approach and leads that to more cost. • Uses UML notations likes: use case, class diagram, communication diagram, development diagram and sequence diagram.
- 26. REFERENCES • Pressman, R. Software Engineering: A Practitioner’s Approach. McGraw- Hill)