white box design techniques

1. White box design
techniques

2. #
Path testing
 A structural test technique
 Requires complete knowledge of the
programs structure.
 Mostly used by the programmers to unit
test their own code.

3. #
Control flow graph
 Control flow graph is a graphical
representation of programs control structure.
 It uses elements : process blocks , decisions ,
junctions.
Process block:
Process A

4. #
Control flow graph (contd..)
 Process block is a sequence of program
statements uninterrupted by either decisions
or junctions
 A process block can be one statement or
hundreds of statements or instructions.
 A process has one entry and one exit
 A program does not jump into or out of the
process.

5. #
Control flow graph(contd..)
Decision :
 A decision is a program point at which the
control flow can diverge
 When most decisions are two way some are
three way branches in control flow.
 A case statement is a multi way branch or
decision
If
A=B no
yes

6. #
Control flow graph(contd..)
junction :
 A junction is a point in the program where the
control flow can merge.
 Examples of junction : goto, continue
 A case statement is a multi way branch or
decision
1 2

7. #
Flow graph , flow chart
 White box testing is the detailed investigation
of internal logic and structure of the code
 White box testing is also called glass testing
or open box testing.

8. #
Path testing
 A path through a program is a sequence of
instructions or statements that starts at an
entry, junction , decision and ends at another
junction, decision ,exit.

9. #
fundamental path selection
criteria
• Exercise every path from entry to exit
• Exercise every statement or instruction
at least once.
• Exercise every branch and case
statement in each direction at least
once

10. #
• Path testing : execute all possible control flow
paths through the program. This is restricted
to all all possible entry/exit paths through the
program.
100% path coverage
Statement testing
Execute all statements in the program at least
once under some test
100% statement coverage
Branch testing
100% branch coverage