# Boundary Value Test Cases, Robust Cases and Worst Case Test Cases

Generate boundary Value analysis, robust and worst-case test case for the program to find the median of three numbers. Its input is a triple of positive integers (say x, y, and z) and the minimum value can be 100 and maximum can be 500.

Median of three numbers is the middle number when all three numbers are sorted. Example –
`10, 40, 20`
In this case, the median is 20 (10, 20, 40). 1. Boundary Value Test Cases are –
```for x, y, z :
min value = 100
close to min = 101
nominal = 300
close to max = 499
max = 500 ```
Test cases are,
`4*3 + 1 = 13 `
X Y Z Median
100 300 300 300
101 300 300 300
300 300 300 300
499 300 300 300
500 300 300 300
300 100 300 300
300 101 300 300
300 499 300 300
300 500 300 300
300 300 100 300
300 300 101 300
300 300 499 300
300 300 500 300
2. Robust Test Cases – Here, we go outside the legitimate boundary, it is an extension of boundary value analysis.
```for x, y, z :
min value : 100
close to min : 101
nominal : 300
close to max : 499
max : 500
lesser than min value : 99
larger than max value : 501  ```
Total test cases,
`= 6*n+1 = 6*3+1 = 19 `
So there will be extra 6 cases apart from the above 13 cases –
X Y Z
99 300 300
501 300 300
300 99 300
300 501 300
300 300 99
300 300 501
3. Worst Test Cases – If we reject “single” fault assumption theory of reliability, and consider cases where more than 1 variable has extreme values, then it is known as worst case analysis. Total no. of test cases,
`5^n = 5^3 = 125 cases `
X Y Z Median
100 100 100 100
101 100 100 100
300 100 100 100
499 100 100 100
500 100 100 100
100 101 100 100
101 101 100 101
300 101 100 101
499 101 100 101
Mathematically, the test cases will be a cross product of 3 sets –
```  {100, 101, 300, 499, 500}
x {100, 101, 300, 499, 500}
x {100, 101, 300, 499, 500}```
Let set A,
`= {100, 101, 300, 499, 500}`
So, the set of worst cases will be represented by,
`= A x A x A `

Previous
Next