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.