# Black Box – BVT on 3 Variables software testing

## Black Box – BVT on 3 Variables software testing

Suppose we have three variable x,y, and z to test.

The range of x: 0 to 100

The range of y : 20 to 60

The range of z : 80 to 100

 X y z Min 0 20 80 Min+ 1 21 81 Nominal 50 40 90 Max- 99 59 99 Max 100 60 100

Figure: Testing points detected in Simple Boundary Value Testing.

Total Test cases =

(Number of variables * Number of testing points without nominal ) + (1 for  Nominal)

13=(3*4)+1

• There are total 3 variables X,Y and Z
• There are 4 possible values like min, min+, max- and max
• 1 is for nominal

Logic:

When we make test cases, we will fix the nominal value of two variables and change the values of the third variable.

For example

• We will fix nominal values of X and Y and make a combination of these values with each value of Z variable.

Fix nominal values of X and Y are 50,40, and we will compare these two values with 80,81,90,99 and 100.

• We will fix nominal values of Y and Z and will make a combination of these values with each value of X variable.

Fix nominal values of Y and Z are 40, 90, and we will make a combination of  these two values with 0,1,50,99,100

• We will fix nominal values of X and Z and will make a combination of these values with each value of Y variable.

Fix nominal values of X and Z are 50, 90 , and we will make combination of  these two values with 20,21,40,59,60

We can generate 13  test cases from both variables X, Y and Z

 Test Case# X,Y,Z Test Case # X,Y,Z Test Case # X,Y,Z 1 50,40,80 2 50,40,81 3 50,40,90 4 50,40,99 5 50,40,100 6 0,40,90 7 1,40,90 8 99,40,90 9 100,40,90 10 50,20,90 11 50,21,90 12 50,59,90 13 50,60,90

Figure: Test cases generated  in Simple Boundary Value Testing using 3 variables.

Prof.Fazal Rehman Shamil (Available for Professional Discussions)
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