Black Box – BVT software testing

This technique says that mostly errors are occurred at boundaries. For example, if we have a variable marks and the range of variable marks is from 1 to 100 then we can say that we should test them 100 times  and one time for each value.

We will test that if marks are 1 then 1 is correctly entertained by our software or not?

We will test that if marks are 2 then 2  is correctly entertained by our software or not?

We will test that if marks are 3 then 3 is correctly entertained by our software or not? And so on for each value of marks.

Problem:

This is very exhausting process and waste a lot of time and budget  if we test values of only one variable hundred times.

Solution:

 Solution to this problem is simple boundary value testing

Simple Boundary value testing of one variable:

Boundary value testing says that errors are mostly occurs at boundaries , so we should only test the values at boundaries.

For example we can test the values at 5 different points like

Min Min+ Nominal Max- Max

Here in case of marks, the range of marks is 1 to 100 . So if we find these five values then;

Min Min+ Nominal Max- Max
1 2 50 99 100

Min:

Min is the minimum value among the data range.

Min+:

Min+  is the minimum value +1  among the data range.

Nominal:

Nominal value can be any typical value which is far away from boundaries. For example here we chose 50 as nominal but we can also chose 51, 52, 53, 49, 48 or any value that is typical value and far away from boundaries. As we see that 50 have a very large distance against 1 and 2. Similarly 50 have a very large distance against 99 and 100. So 50 can be nominal value.

Max-:

Max- is the Maximum value -1 among the data range.

Max:

Max is the maximum value among the data range.

Test cases:

We can generate 5 test cases from one  variable marks as

Test case # 1 : To test 1

Test case # 2 : To test 2

Test case # 3 : To test 50

Test case # 4 : To test 99

Test case # 5 : To test 100