Fundamentals of Software Engineering
- 2. 2 Black-box Testing âą Complements white-box testing by uncovering different classes of errors âą Focuses on the functional requirements and the information domain of the software âą Used during the later stages of testing after white box testing has been performed âą The tester identifies a set of input conditions that will fully exercise all functional requirements for a program âą The test cases satisfy the following: â Reduce, by a count greater than one, the number of additional test cases that must be designed to achieve reasonable testing â Tell us something about the presence or absence of classes of errors, rather than an error associated only with the specific task at hand
- 3. 3 Black-box Testing Categories âą Incorrect or missing functions âą Interface errors âą Errors in data structures or external data base access âą Behavior or performance errors âą Initialization and termination errors
- 4. 4 Questions answered by Black-box Testing âą How is functional validity tested? âą How are system behavior and performance tested? âą What classes of input will make good test cases? âą Is the system particularly sensitive to certain input values? âą How are the boundary values of a data class isolated? âą What data rates and data volume can the system tolerate? âą What effect will specific combinations of data have on system operation?
- 5. Graph-based testing ïź Begins by creating a graph of important objects and their relationships and then devising a series of tests that will cover the graph so that each object and relationship is exercised and errors are uncovered. These slides are designed to accompany Software Engineering: A Practitionerâs Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman. 5 new file menuselect generates (generationtime ïŒ 1.0sec) document window document tex t is representedas contains Attributes: backgroundcolor: white text color: default color or preferences (b) object #1 Directedlink (link weight) object #2 object # 3 Undirectedlink Parallel links Nodeweight (value ) (a) allows editing of
- 6. 6 Equivalence Partitioning âą A black-box testing method that divides the input domain of a program into classes of data from which test cases are derived âą An ideal test case single-handedly uncovers a complete class of errors, thereby reducing the total number of test cases that must be developed âą Test case design is based on an evaluation of equivalence classes for an input condition âą An equivalence class represents a set of valid or invalid states for input conditions âą From each equivalence class, test cases are selected so that the largest number of attributes of an equivalence class are exercise at once
- 7. 7 Guidelines for Defining Equivalence Classes âą If an input condition specifies a range, one valid and two invalid equivalence classes are defined â Input range: 1 â 10 Eq classes: {1..10}, {x < 1}, {x > 10} âą If an input condition requires a specific value, one valid and two invalid equivalence classes are defined â Input value: 250 Eq classes: {250}, {x < 250}, {x > 250} âą If an input condition specifies a member of a set, one valid and one invalid equivalence class are defined â Input set: {-2.5, 7.3, 8.4} Eq classes: {-2.5, 7.3, 8.4}, {any other x} âą If an input condition is a Boolean value, one valid and one invalid class are define â Input: {true condition} Eq classes: {true condition}, {false condition}