Software Test Case Design Methods - Black Box Testing Methods

Black box testing focuses on:
- testing thefunctional aspect of the software.
- input conditions are derived that will test all functional requirements.
- set of test cases that finds incorrect or missing functions.
- interface errors.
- data structure errors.
- external database excess errors.
- performance errors.
- initialization and termination errors.

Black box techniques include:

- Graph based testing is a black-box testing technique that uses objects that are modeled in software and the relationships among these objects. Steps involved in designing test cases using graph based testing are:

STEP 1: Create a graph of software objects and identify the relationship of these objects.
STEP 2: Traverse the graph to define test cases.

- Equivalence Testing
A black box testing technique which divides the input domain into partitions or into sets of data from which test cases can be derived. These test cases are used to uncover errors. It makes use of equivalence classes which are sets of valid and invalid states that an input may be in.

- Boundary Value Testing
It is a black box testing method that uses the boundaries of the input domain to derive test cases. If input condition specifies range bounded by n and m, the test cases that can be derived use values n and m, just above n and m, just below n and m.

If input condition specifies number of values, the test cases that can be derived are use the minimum, use the maximum, just above and below minimum, just above and below maximum.