Same as path testing make flow graph.

Now, make Decision-to-Decision table in which consecutive nodes are counted as an individual.

On the basis of above table, create DD graph.

After DD graph, it is time to figure out du and dc paths. For this, create ‘ defined node and used at node’ table to view variable’s definition and initialization.

From above table, find du and dc paths.

Based on du and dc paths create test cases, covering each and every variable definition and usage.

In this, we will drive test cases using Data flow testing approach by considering the Quadratic equation example. The first step is to create a flow graph from the code of the Quadratic Equation.

Using the flow graph, create a Decision to Decision Graph ( DD Graph) by converting each set of consecutive nodes into a single node.

Replace these numbers with correspondent DD nodes.

Create a Defined and Used node table to get a clear view of variable usage.

On the basis of the above table, we will generate du and dc path respectively.

All the ‘Y’ in the above table are DC path and ‘Path nodes’ are DU paths.

Now, create the test cases from input provided by the user in such a way that all the paths get covered.

Here’s is the triangle problem code.

In path testing, first we create the flow graph of the triangle problem based on the program which shows the flow and possible paths.

Once the flow graph is created, with the help of it list all the consecutive nodes and assign an alphabet to them.

After creating DD Table, it’s time to generate DD graph through which Cyclomatic complexity and the possible path will be gathered.

Using DD graph ( Decision to Decision graph ), calculate the cyclomatic complexity which tells all the independent paths.

Cyclomatic complexity = E – N + 2P

= 20-16+2

=6

Possbile paths are:

-A,B,C,D,E,F,G,K,L,M,O,P
-A,B,C,D,E,F,H,I,K,L,M,O,P
-A,B,C,D,E,F,H,J,K,L,M,O,P
-A,B,C,D,K,L,M,O,P
-A,B,C,D,K,L,M,N,O,P
-A,B,K,L,M,O,P

Based on these paths, we will create Test cases.

The first step is to create a flow graph using quadratic equation program.

After creating the flow graph, it’s time to make a Decision-to-Decision Graph (DD Graph). List one by one consecutive nodes and assign an alphabet.

Generate a DD graph.

Now, calculate cyclomatic complexity which represent the number of possible paths,

=E − N + 2P

=16-13+2

=5

After calculating cyclomatic complexity, generate independent paths.

– A,B,D,F,H,I,J,L,M
– A,B,D,F,G,I,J,L,M
– A,B,D,E,I,J,L,M
– A,B,C,I,J,L,M
– A,B,C,I,J,K,L,M

The last step is to formulate test cases based on the calculated independent paths.