Cause Effect Graphing Technique

Cause-effect graphs in black box testing

• Captures the relationships between specific combinations of inputs (causes) and outputs (effects)–Deals with specific cases, –Avoids combinatorial explosion–Explore combinations of possible inputs

• Causes/effects are represented as nodes of a cause effect graph

• The graph also includes a number of intermediate nodes linking causes and effects

Cause effect graph, an example

4Proposed by G. J. Mayers

• File management:

• If the character of the first column is ‘A’ or ‘B’, and the second

column is a number, then the file is considered updated.

• If the first character is erroneous, print message X12

• If the second column is not a number, print message X13

Cause effect graph: Decision Table

5Proposed by G. J. Mayers

Cause effect graph: Methodology

6Proposed by G. J. Mayers

Test technique based on cause effect graph consists in the following steps:

1.Decompose the unit to be tested, If it has many functionalities

2.Identify the causes

3.Identify the effects

4.Establish the graph of relations between causes and effects

5.Complete the graph by adding constraints between causes and effects

6.Convert the graph to a decision table

7.Produce a test per line after simplification of the table