Software testing
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This document provides an overview of software testing fundamentals and processes. It discusses verification and validation, which involve checking that software meets specifications and customer needs. Testing establishes the existence of defects, while debugging involves locating and correcting defects. There are different types of testing like unit, integration, system and acceptance testing. Test planning is important and involves aspects like requirements traceability, test cases, schedules and constraints. Testing strategies include top-down, bottom-up and thread testing. The document also defines terms like error, fault and failure and discusses black box, alpha, beta, interface, stress and clean room testing.
Software testing
- 1. SOFT SKILLS AND PERSONALITY DEVELOPMENT TOPIC: SOFTWARE TESTING SUBMITTED BY NAME: MOHAMMAD AZHAR UD DIN ROLL NO:13YYSB6009
- 2. SOFTWARE TESTING VERIFICATION & VALIDATION: Verification & validation process involves checking process which make sure that software conforms to its specification and meets the needs of the customers . Therefore verification & validation starts with requirements review, continues through design & code reviews to product testing . • Verification :”Are we building the product right ?” verification involves checking whether the program satisfies its specification. • Validation :”Are we building the right product?” validation involves checking whether the program implementation meets the expectation of the software customer.
- 3. • TESTING & DEBUGGING when defects have been found in a program, they must be discovered and removed . This is known as debugging . Testing establishes the existence of defects . Debugging involves location and correction these defects . o Defect testing and debugging are distinct processes . o Verification & validation is concern with establishing the existence of defects in a programs . o After the defects is discovered , it is corrected and the system is then re-tested ,this form of testing is known as regression testing Testing Results Specification Testing Cases Locate error Design Error repair Repair error Re-test Program
- 4. TESTING FUNDAMENTALS What is error, fault, failure? • Error: refers to the difference between the actual output and the correct output of the software. Error is a measure of the difference between the actual and ideal values. • Fault: is a condition that causes the software to fail to perform its required function. • Failure: is the inability of a system to perform a required function according to its specification. A software failure occurs if the behavior of the software is different from the specified behavior . A failure is produced only when there is fault in the system. however ,presence of a fault does not guarantee failure.
- 5. TEST CASE AND TEST CRITERIA: Having proper test cases is central to successful testing . Determining a set of test cases such that successful execution of all of them implies that there are no error in the program, would be an ideal situation. Each test cases cost money, as efforts is needed to generate the test case, machine time to execute the program for that case and more efforts to evaluate the results. • Therefore the number of test cases needed to detect errors due to reliability and economic constraints, connected with set of cases, must be minimized. The goal of selecting test cases to ensure that if there is an error in the program, it is executed by one the test cases. • There are two aspects of test case selection: • Reliability: A criterion is reliable if, all the test cases that satisfy the criterion detect the same errors. This means that every set will detect the same error. • Validity: A criterion is valid if for any error in the program, there is some set satisfying the criterion, which will revel the error.
- 6. TESTING PROCESS The testing process consists of 5 in stages: 1. Unit testing: involves testing of individual components. Individual components are tested to ensure that they operated correctly. 2. Module testing: concern testing of collection of dependent components. A module encapsulates related component so can be tested without other system module. 3. Sub-System testing: involves testing collection of modules integrated into sub-systems. Sub- system may be independently design and implemented. 4. System testing: involves testing the complete system prior to delivery. 5. Acceptance testing: is the final stage of the testing process before it is accepted by the customber. The system is tested by users to check that is satisfies requirements. Acceptance testing is something called alpha testing
- 8. TEST PLANNING: Test planning involves setting standard for the testing process. o Test plans are for software engineers involves in design and testing the system. o Test plans allow technical staff to get an overall picture of the system test. 1. The testing process: is a description of the major phase of testing process. 2. Requirements traceability: involves planning so that all requirements are individually tested. 3. Tested item: concern the product of the software process to be specified, which are to be tested. 4. Testing schedule: is an overall testing scheduling and resource allocation for this schedule. 5. Test record procedure : concern recording the results of the tests systematically. 6. Hardware and software requirements : specify the software tools required and estimated hardware utilization. 7. Constraints : are the constrains affecting the testing process such as staff shortage.
- 9. • TESTING STRATEGIES The 5 testing strategy are : 1. Top-down testing 2. Bottom-up testing 3. Thread testing 4. Stress testing Top-down testing: a. Top-down testing strategy is used in conjunction with top-down development. b. This strategy detects architecture-related errors. c. Top-down testing may need system infrastructure before any testing is possible. d. Strict top-down testing may need system be difficult to implement because it may be difficult to develop program stubs.
- 10. TYPES OF TESTING Black Box Testing • This is also called as functional testing. • Test are derived from program or module component specification. • This system is considered as a black box whose behavior can only be • Determined by studying its inputs and related output.
- 11. ALPHA TESTING • Acceptance testing is sometime called alpha testing. • The alpha testing processing contains until the system developer and the client agree that the testing delivered system is an acceptable implements of the system requirements. • This testing will be done at organization in presence of client. BETA TESTING • When a system is to be marked as a software product , it is tested by process called beta testing. • This involves delivered a system to a number of potential customers who agree to use that system.
- 12. • BOTTOM-UP TESTING : a. Bottom-up testing is appropriate for object-oriented system, since individual object can be tested using their own test drivers. They can then be integrated and the object collection can be tested. b. Some difference between top-down and bottom-up testing are as follows: In the top-down approach, stubs must be written, and in the others, drivers need to be written. Top-down testing is advantages if major flows occurs towards the top of the hierarchy, while bottom-up is advantages if the major flows occur towards the bottom. THREAD TESTING: Thread testing is an event-based approach where test are performed based on the events which trigger system actions. • Thread testing involves identify and executing each possible processing thread. • Thread testing starts with single events threads and then goes on to multiple event threads. • Threads testing strategy is most suitable for real-time and object –oriented systems. • Complete thread testing is impossible due to large number of event combination.
- 13. CLEAN ROOM TESTING: • This is development on static techniques for program specification and statistical testing for system reliability certification. • Clean room is based on two principles. • Produce zero faults or near zero faults INTERFACE TESTING Interface testing takes place when modules or subsystem are integrated to create larger system. The objective of interface testing is to detect faults which may have been introduced into the system.
- 14. STRESS TESING : Stress testing involves planning a series of test where the where the load is steadily increased. The tests are continued beyond the maximum design load, until the system fails. a. Exercising the system beyond its maximum design load often causes defects to come to light. b. It is particularly relevant to distributed system which can exhibition severe degradation as a network becomes overloaded.
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