Validation testing in software engineering

Related to software engineering and here some detail about validation testing

1. SUPERIOR GROUP OF COLLEGES, SARGODHA

2. Software Engineering Lecture Prof. MUHAMMAD BILAL QURESHI SUPERIOR GROUP OF COLLEGES, SARGODHA

3. Validation testing SUPERIOR GROUP OF COLLEGES, SARGODHA

4. Validation testing Validation testing follows integration testing The distinction between conventional and object-oriented software disappears and Focuses on user-visible actions and user-recognizable output from the system SUPERIOR GROUP OF COLLEGES, SARGODHA

5. Validation-Test Criteria • Designed to ensure that All functional requirements are satisfied , All behavioral characteristics are achieved , All performance requirements are attained • Documentation is correct • Usability and other requirements are met (e.g ., transportability , compatibility, error recovery, maintainability ) • After each validation test – The function or performance characteristic conforms to specification and is accepted – A deviation from specification is uncovered and a deficiency list is created SUPERIOR GROUP OF COLLEGES, SARGODHA

6. Configuration Review • The intent of this review is to ensure that all elements of the software configuration have been properly developed, are cataloged , and have the necessary detail to encourage the support activities. SUPERIOR GROUP OF COLLEGES, SARGODHA

7. Alpha and Beta Testing • Alpha testing conducted at the developer’s site by end users – Software is used in a natural setting with developers watching intently – Testing is conducted in a controlled environment • Beta testing conducted at end-user sites – Developer is generally not present – It serves as a live application of the software in an environment that cannot be controlled by the developer – The end-user records all problems that are encountered and reports these to the developers at regular intervals • After beta testing is complete, software engineers make software modifications and prepare for release of the software product to the entire customer base SUPERIOR GROUP OF COLLEGES, SARGODHA

8. SYSTEM TESTING SUPERIOR GROUP OF COLLEGES, SARGODHA

9. SYSTEM TESTING System testing is a series of different tests whose purpose is to fully exercise the computer based system • Recovery testing – Tests for recovery from system faults – Forces the software to fail in a variety of ways and verifies that recovery is properly performed – Tests reinitialization , check pointing mechanisms, data recovery, and restart for correctness SUPERIOR GROUP OF COLLEGES, SARGODHA

10. Security Testing – Verifies that protection mechanisms built into a system will, in fact , protect it from improper access. • Stress testing – Executes a system in a manner that demands resources in abnormal quantity, frequency, or volume SUPERIOR GROUP OF COLLEGES, SARGODHA

11. Performance Testing – Tests the run-time performance of software within the context of an integrated system – Often coupled with stress testing and usually requires both hardware and software instrumentation – Can uncover situations that lead to degradation and possible system failure SUPERIOR GROUP OF COLLEGES, SARGODHA

12. Deployment Testing – Also known as configuration testing – It examines all installations procedures that will be used by customers SUPERIOR GROUP OF COLLEGES, SARGODHA

13. INTERNAL AND EXTERNAL VIEWS OF TESTING SUPERIOR GROUP OF COLLEGES, SARGODHA

14. INTERNAL AND EXTERNAL VIEWS OF TESTING The first test approach takes an external view and is called black-box testing . The second requires an internal view and is termed white-box testing. SUPERIOR GROUP OF COLLEGES, SARGODHA

15. White box testing • White box testing is also called as glass-box testing • Using white-box testing methods can derive test cases that – guarantee that all independent paths within a module have been exercised at least once – exercise all logical decisions on their true and false sides – execute all loops at their boundaries and within their operational bounds – exercise internal data structures to ensure their validity SUPERIOR GROUP OF COLLEGES, SARGODHA

16. Basis path testing • Basis path testing is a white-box testing technique • The basis path method enables the test-case designer to derive a logical complexity measure of a procedural design and use this measure as a guide for defining a basis set of execution paths • Flow Graph Notation: – a simple notation for the representation of control flow, called a flow graph – It also know as program graph SUPERIOR GROUP OF COLLEGES, SARGODHA

17. ` • Arrows called edges or links represent flow of control • Circles called flow graph nodes represent one or more actions • Areas bounded by edges and nodes called regions • A predicate node is a node containing a condition SUPERIOR GROUP OF COLLEGES, SARGODHA

18. • Independent program paths: – An independent path is any path through the program that introduces at least one new set of processing statements or a new condition – independent path must move along at least one edge that has not been traversed( pass through ) before the path is defined – An independent path is any path through the program that introduces at least one new set of processing statements or a new condition – independent path must move along at least one edge that has not been traversed before the path is defined SUPERIOR GROUP OF COLLEGES, SARGODHA

19. – Example : SUPERIOR GROUP OF COLLEGES, SARGODHA

20. • Deriving test cases – Using the design or code as a foundation, draw a corresponding flow graph. – Determine the cyclomatic complexity of the resultant flow graph . – Determine a basis set of linearly independent paths. – Prepare test cases that will force execution of each path in the basis set SUPERIOR GROUP OF COLLEGES, SARGODHA

21. • Graph matrices – A data structure, called a graph matrix, can be quite useful for developing a software tool that assists in basis path testing – A graph matrix is a square matrix whose size (i.e., number of rows and columns) is equal to the number of nodes on the flow graph SUPERIOR GROUP OF COLLEGES, SARGODHA

22. Black box testing • Black-box testing, also called behavioral testing • Black-box testing attempts to find errors in the following categories: – incorrect or missing functions – interface errors – errors in data structures or external database access – behavior or performance errors – initialization and termination errors. SUPERIOR GROUP OF COLLEGES, SARGODHA

23. Graph-based testing methods The first step in black-box testing is to understand the objects that are modeled in software and the relationships that connect these objects. Once this has been accomplished , the next step is to define a series of tests that verify “all objects have the expected relationship to one another” [Bei95]. Stated in another way, software testing begins by creating a graph of important objects and their relationships and then planning a series of tests that will cover the graph so that each object and relationship is exercised and errors are uncovered . SUPERIOR GROUP OF COLLEGES, SARGODHA

24. To accomplish these steps, you begin by creating a graph —a collection of nodes that represent objects , links that represent the relationships between objects, node weights that describe the properties of a node (e.g., a specific data value or state behavior ), and link weights that describe some characteristic of a link. Nodes are represented as circles connected by links that take a number of different forms . A directed link (represented by an arrow) indicates that a relationship moves in only one direction. A bidirectional link, also called a symmetric link , implies that the relationship applies in both directions. Parallel links are used when a number of different relationships are stablished between graph nodes. SUPERIOR GROUP OF COLLEGES, SARGODHA

25. These test cases are designed in an attempt to find errors in any of the relationships. Beizer describes a number of behavioral testing methods that can make use of graphs: Transaction flow modeling. Finite state modeling Data flow modeling. Timing modeling. SUPERIOR GROUP OF COLLEGES, SARGODHA

26. Equivalence Partitioning • Equivalence partitioning is a black-box testing method that divides the input domain of a program into classes of data from which test cases can be derived • equivalence classes for an input condition. Using concepts introduced in the preceding section, if a set of objects can be linked by relationships that are symmetric, transitive, and reflexive , an equivalence class is present SUPERIOR GROUP OF COLLEGES, SARGODHA

27. • Equivalence classes may be defined according to the following guidelines: 1. If an input condition specifies a range, one valid and two invalid equivalence classes are defined. 2. If an input condition requires a specific value, one valid and two invalid equivalence classes are defined. 3. If an input condition specifies a member of a set, one valid and one invalid equivalence class are defined. 4. If an input condition is Boolean, one valid and one invalid class are defined. SUPERIOR GROUP OF COLLEGES, SARGODHA

28. Boundary Value Analysis • A greater number of errors occurs at the boundaries of the input domain rather than in the “center.” It is for this reason that boundary value analysis (BVA) has been developed as a testing technique • Boundary value analysis leads to a selection of test cases that exercise bounding values SUPERIOR GROUP OF COLLEGES, SARGODHA

29. • Guidelines for BVA are similar in many respects to those provided for equivalence partitioning: – If an input condition specifies a range bounded by values a and b, test cases should be designed with values a and b and just above and just below a and b. – If an input condition specifies a number of values, test cases should be developed that exercise the minimum and maximum numbers.Values just above and below minimum and maximum are also tested. – Apply guidelines 1 and 2 to output conditions – If internal program data structures have prescribed boundaries (e.g., a table has a defined limit of 100 entries), be certain to design a test case to exercise the data structure at its boundary. SUPERIOR GROUP OF COLLEGES, SARGODHA

30. Orthogonal Array Testing • Orthogonal array testing can be applied to problems in which the input domain is relatively small but too large to accommodate complete testing • The orthogonal array testing method is particularly useful in finding region faults • a single parameter value makes the software fault. These faults are called single mode faults • If there exists a consistent problem when specific levels of two parameters occur together, it is called a double mode fault SUPERIOR GROUP OF COLLEGES, SARGODHA

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