Structural (White-Box) Structural (White-Box) TestingTesting

Software Testing Module

Dr. Samer Hanna

Outline

• Path Testing

• Control Flow Graph

• DD-Path Graph

• Questions

Path testing

• Structural testing method

• Based on the source code / Pseudocode of the program or the system, and NOT on its specification

Example: Find the Control Flow Graph (CFG) for the Triangle Problem

CFG

CFG

DD – Path Graph

• A CFG can be broken into DD-paths

• The resulting graph is called a DD-path graph of the program

DD – Path Graph

DD: Decision – to – Decision path• A DD-path is a sub-path in a program graph fulfilling

one of the conditions below:1. It consists of a single node with indeg = 0

2. It consists of a single node with outdeg = 0

3. It consists of a single node with indeg ≥ 2 or outdeg ≥ 2

4. It consists of a single node with indeg = 1 and outdeg = 1

5. It is a maximal chain of length ≥ 1

DD – Path Graph

Node DD-Path Name

Case of Definition

1 Source 1

2 - 4 A 5

5 B 3

6 C 4

7 D 4

8 E 3

… … …

19 Sink 2

CFG to DD-Path

Independent (basis) paths

Independent path is a path through a DD-path graph of the program which cannot be reproduced from other paths

Independent (basis) paths

Independent (basis) paths