176 SOF T WARE ENGINEERING AND 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 ...