Functional / Black-Box TestingSabtu, 2010-03-06, 11:04:38
Oleh : Administrator
 In functional testing the structure of the program is not considered. Test cases are decided on the basis of the requirements or specifications of the program or module and the internals of the module or the program are not considered for selection of test cases.
Functional testing refers to testing that involves only observation of the output for certain input values, and there is no attempt to analyze the code, which produces the output. The internal structure of the program is ignored. For this reason, functional testing is sometimes referred to as black-box testing (also called behavioral testing) in which the content of a black-box is not known and the function of black box is understood completely in terms of its inputs and outputs.
Black-box testing, also called behavioral testing, focuses on the functional requirements of the software. Black-box testing enables the software engineer to derive sets of input conditions that will fully exercise all functional requirements for a program.
Other names for black-box testing (BBT) include specifications testing, behavioral testing, data-driven testing, functional testing, and input/outputdriven testing.
In black-box testing, the tester only knows the inputs that can be given to the system and what output the system should give. In other words, the basis for deciding test cases in functional testing is the requirements or specifications of the system or module. This form of testing is also called functional or behavioral testing.
Black-box testing is not an alternative to white-box techniques; rather, it is a complementary approach that is likely to uncover a different class of errors than white-box methods.
Black-box testing identifies the following kinds of errors:
- Incorrect or missing functions.
- Interface missing or erroneous.
- Errors in data model.
- Errors in access to external data source.
When these errors are controlled then:
Function(s) are valid.
A class of inputs is validated.
Validity is sensitive to certain input values.
The software is valid and dependable for a certain volume of data or transactions.
Rare specific combinations are taken care of.
Black-box testing tries to answer the following questions:
- How is functional validity tested?
- How are system behavior and performance tested?
- How are the boundaries of a data class isolated? How will the specific combinations of data affect system operation?
- What data rates and data volume can the system tolerate? Is the system particularly sensitive to certain input values?
- What effect will specific combinations of data have on system operation?
By applying black-box techniques, we derive a set of test cases that satisfy the following criteria:
- Test cases that reduce by a count that is greater than one.
- Test cases that tell us something about the presence or absence of classes of errors.
Source: Agarwal, B. B. et.al.2010.Software Engineering and Testing An Introduction. Jones and Bartlett Publishers, LLC. Sudbury. Massachusetts |
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