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Black-box or behavioral testing knowing the specified function a product is to perform and demonstrating correct operation based solely on its specification without regard for its internal logic. White-box or glass-box testingknowing the internal workings of a product, tests are performed to check the workings of all independent logic paths. Basis Path TestingWhite-box technique usually based on the program flow graph The cyclomatic complexity of the program computed from its flow graph using the formula V(G) = E N + 2 or by counting the conditional statements in the PDL representation and adding 1 Determine the basis set of linearly independent paths (the cardinality of this set id the program cyclomatic complexity) Prepare test cases that will force the execution of each path in the basis set. Control Structure Testing White-box techniques focusing on control structures present in the software Condition testing (e.g. branch testing) focuses on testing each decision statement in a software module, it is important to ensure coverage of all logical combinations of data that may be processed by the module (a truth table may be helpful) Data flow testing selects test paths based according to the locations of variable definitions and uses in the program (e.g. definition use chains) Loop testing focuses on the validity of the program loop constructs (i.e. simple loops, concatenated loops, nested loops, unstructured loops), involves checking to ensure loops start and stop when they are supposed to (unstructured loops should be redesigned whenever possible) Graph-based Testing Methods Black-box methods based on the nature of the relationships (links) among the program objects (nodes), test cases are designed to traverse the entire graph Transaction flow testing (nodes represent steps in some transaction and links represent logical connections between steps that need to be validated) Finite state modeling (nodes represent user observable states of the software and links represent transitions between states) Data flow modeling (nodes are data objects and links are transformations from one data object to another) Timing modeling (nodes are program objects and links are sequential connections between these objects, link weights are required execution times) Equivalence Partitioning Black-box technique that divides the input domain into classes of data from which test cases can be derived An ideal test case uncovers a class of errors that might require many arbitrary test cases to be executed before a general error is observed Equivalence class guidelines: If input condition specifies a range, one valid and two invalid equivalence classes are defined If an input condition requires a specific value, one valid and two invalid equivalence classes are defined If an input condition specifies a member of a set, one valid and one invalid equivalence class is defined If an input condition is Boolean, one valid and one invalid equivalence class is defined Boundary Value Analysis Black-box technique that focuses on the boundaries of the input domain rather than its center BVA guidelines: If input condition specifies a range bounded by values a and b, test cases should include a and b, values just above and just below a and b If an input condition specifies and number of values, test cases should be exercise the minimum and maximum numbers, as well as values just above and just below the minimum and maximum values Apply guidelines 1 and 2 to output conditions, test cases should be designed to produce the minimum and maxim output reports If internal program data structures have boundaries (e.g. size limitations), be certain to test the boundaries. Comparison Testing Black-box testing for safety critical systems in which independently developed implementations of redundant systems are tested for conformance to specifications Often equivalence class partitioning is used to develop a common set of test cases for each implementation Orthogonal Array Testing Black-box technique that enables the design of a reasonably small set of test cases that provide maximum test coverage Focus is on categories of faulty logic likely to be present in the software component (without examining the code) Priorities for assessing tests using an orthogonal array Detect and isolate all single mode faults Detect all double mode faults Mutimode faults Specialized Testing Graphical user interfaces. Client/server architectures. Documentation and help facilities. Real-time systems 1. Task testing (test each time dependent task independently) 2. Behavioral testing (simulate system response to external events) 3. Intertask testing (check communications errors among tasks) |
