Tutorial-6: To Generate Equivalence Class Test Cases-For the Triangle Problem
“The triangle program takes three integers, a, b and c as input. These are taken to be the sides of the triangle.
The output of the program can be either of: Equilateral Triangle, Isosceles Triangle, Scalene or “Not a Triangle”.
We can use these to identify output (range) equivalence classes as under:
01 = {<a, c=”” b,=””> : the triangle is equilateral}
</a,>
02 = {<a, c=”” b,=””> : the triangle is isosceles}
</a,>
03 = {<a, c=”” b,=””> : the triangle is scalene}
</a,>
04 = {<a, c=”” b,=””> : sides a, b and c do not form a triangle}</a,>
Objective of this Tutorial: To apply the four techniques of equivalence class partitioning one by one & generate appropriate test cases?
1) Weak Normal Equivalence Class: The four weak normal equivalence class test cases can be defined as under
| Test Case ID | Side “a” | Side “b” | Side “c” | Expected Output |
| WN1 | 5 | 5 | 5 | Equilateral Triangle |
| WN2 | 2 | 2 | 3 | Isosceles Triangle |
| WN3 | 3 | 4 | 5 | Scalene Triangle |
| WN4 | 4 | 1 | 2 | Not a Triangle |
2) Strong Normal Equivalence Class: Since no valid subintervals of variables a, b and c exist, so the strong normal equivalence class test cases are identical to the weak normal equivalence class test cases.
3) Weak Robust Equivalence Class: Considering the invalid values for a, b and c yields the following additional weak robust equivalence class test cases
| Test Case ID | Side “a” | Side “b” | Side “c” | Expected Output |
| WR1 | 1 | 5 | 5 | Invalid Value of a |
| WR2 | 5 | -1 | 5 | Invalid Value of b |
| WR3 | 5 | 5 | -1 | Invalid Value of c |
| WR4 | 201 | 5 | 5 | Out of Range Value of a |
| WR5 | 5 | 201 | 5 | Out of Range Value of a |
| WR6 | 5 | 5 | 201 | Out of Range Value of a |
4) Strong Robust Equivalence Class: Test Cases falling under this category are
| Test Case ID | Side “a” | Side “b” | Side “c” | Expected Output |
| SR1 | -1 | 5 | 5 | Invalid Value of a |
| SR2 | 5 | -1 | 5 | Invalid Value of b |
| SR3 | 5 | 5 | -1 | Invalid Value of c |
| SR4 | -1 | -1 | 5 | Invalid Value of a & b |
| SR5 | 5 | -1 | -1 | Invalid Value of b & c |
| SR6 | -1 | 5 | -1 | Invalid Value of a & c |
| SR7 | -1 | -1 | -1 | Invalid Value of a , b & c |
It may be noted that the expected outputs describe the invalid input values thoroughly.
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