- Regression testing is the process of testing changes to computer programs to make sure that the older programming still works with the new changes.
- Regression testing is a normal part of the program development process. Test department coders develop code test scenarios and exercises that will test new units of code after they have been written.
- Before a new version of a software product is released, the old test cases are run against the new version to make sure that all the old capabilities still work. The reason they might not work because changing or adding new code to a program can easily introduce errors into code that is not intended to be changed
- The selective retesting of a software system that has been modified to ensure that any bugs have been fixed and that no other previously working functions have failed as a result of the reparations and that newly added features have not created problems with previous versions of the software. Also referred to as verification testing
- Regression testing is initiated after a programmer has attempted to fix a recognized problem or has added source code to a program that may have inadvertently introduced errors
- It is a quality control measure to ensure that the newly modified code still complies with its specified requirements and that unmodified code has not been affected by the maintenance activity
GUI is the abbreviation for Graphic User Interface. It is absolutely essential that any application has to be user-friendly. The end user should be comfortable while using all the components on screen and the components should also perform their functionality with utmost clarity. Hence it becomes very essential to test the GUI components of any application. GUI Testing can refer to just ensuring that the look-and-feel of the application is acceptable to the user, or it can refer to testing the functionality of each and every component involved.
The following is a set of guidelines to ensure effective GUI Testing and can be used even as a checklist while testing a product / application.
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)
2.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:
1.If 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 is defined
4.If an input condition is Boolean, one valid and one invalid equivalence class is defined
3. Boundary Value Analysis
Black-box technique that focuses on the boundaries of the input domain rather than its center
·BVA guidelines:
1.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
2.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
3.Apply guidelines 1 and 2 to output conditions, test cases should be designed to produce the minimum and maxim output reports
4.If internal program data structures have boundaries (e.g. size limitations), be certain to test the boundaries
4. 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
5. 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
1.Detect and isolate all single mode faults
2.Detect all double mode faults
3.Multimode faults
6.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)
4.System testing (check interaction of integrated system software and hardware)
7.Advantages of Black Box Testing
More effective on larger units of code than glass box testing
Tester needs no knowledge of implementation, including specific programming languages
Tester and programmer are independent of each other
Tests are done from a user's point of view
Will help to expose any ambiguities or inconsistencies in the specifications
·Test cases can be designed as soon as the specifications are complete
8.Disadvantages of Black Box Testing
Only a small number of possible inputs can actually be tested, to test every possible input stream would take nearly forever
Without clear and concise specifications, test cases are hard to design
There may be unnecessary repetition of test inputs if the tester is not informed of test cases the programmer has already tried
·May leave many program paths untested
Cannot be directed toward specific segments of code which may be very complex (and therefore more error prone)
·Most testing related research has been directed toward glass box testing
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