Should black box or white box testing be the emphasis for testers?
- Black box testing should be the emphasis for testers/QA.
- White box testing should be the emphasis for developers (i.e. unit tests).
- The other folks who answered this question seemed to have interpreted the question as Which is more important, white box testing or black box testing. I, too, believe that they are both important but you might want to check out this IEEE article which claims that white box testing is more important.
White Box Testing equals Software Unit Test. The developer or a development level tester (e.g. another developer) ensures that the code he has written is working properly according to the detailed level requirements before integrating it in the system.
Black Box Testing equals Integration Testing. The tester ensures that the system works according to the requirements on a functional level.
Both test approaches are equally important in my opinion.
A thorough unit test will catch defects in the development stage and not after the software has been integrated into the system. A system level black box test will ensure all software modules behave correctly when integrated together. A unit test in the development stage would not catch these defects since modules are usually developed independent from each other.
Black Box
1 Focuses on the functionality of the system Focuses on the structure (Program) of the system
2 Techniques used are :
· Equivalence partitioning
· Boundary-value analysis
· Error guessing
· Race conditions
· Cause-effect graphing
· Syntax testing
· State transition testing
· Graph matrix
Tester can be non technical
Helps to identify the vagueness and contradiction in functional specifications
White Box
Techniques used are:
· Basis Path Testing
· Flow Graph Notation
· Control Structure Testing
Condition Testing
Data Flow testing
· Loop Testing
Simple Loops
Nested Loops
Concatenated Loops
Unstructured Loops
Tester should be technical
Helps to identify the logical and coding issues.