What design technique should be used?

Question

Software testing

There is such a problem, I understand that here it is necessary to use the "Design Test" - "Boundary Values" technique, how correct is this?
For example: the salary is 600 USD per month, the commission is
0%, over 2000 - 2%, over 3000 - 5%. What test design techniques
should be used to determine the minimum set of test cases
to test a given functionality, and what will those cases be?
I think the following values ​​should be checked:
-1/0/1/599/600/601/1999/2000/2001/2999/3000/3001/max
But I don't quite understand how to arrange test cases.
Could you help me?

Answer 1

There is such a problem, I understand that here it is necessary to use the "Design Test" - "Boundary Values" technique, how correct is this?

"Boundary values" and you can still "equivalence classes", roughly speaking, group examples.
So yes, that's right.

I think the following values ​​should be checked:
-1/0/1/599/600/601/1999/2000/2001/2999/3000/3001/max

I suppose the case with 600 is debatable for the "minimum set". I'll explain why.
you have the following limits: 0-1999 = 0%
2000 - 2999 = 2%
3000 - inf = 5%
i.e. using the idea of ​​a threshold of $600 it's not really a boundary where percentages change.
And you can also add an "equivalence class" here, such as a multiple or not a multiple of 600, for example,
how does 599 differ from 1? yes, nothing with tz. 600 and 599 or 600 and 1.
Both options (599 and 1) are not 600 and are in the range of 0-599.
Therefore, from the minimum set, I would throw this option out.
Acting on this principle, some would also be thrown out, leaving these options:

1. -1, 0, 1
   
2. 1999, 2000, 2001
   
3. 2999, 3000, 3001
   

Boundary conditions are a condition check, of the form:

if a < b < c:
    do_something
else:
    do_something

And the most common mistakes here are confusing signs (human factor) or forgetting to put the sign = or, on the contrary, adding it when it is not necessary (this is already weak mathematics, sets).
And in the case of such tasks, it is necessary to check whether the element is included in some set or not. And if it is included, then we must also understand what set it is included in.
For example. there is such an error: x > 3000 = 5%, i.e. here is an example when they forgot to put "=" and the value 3000 fell into the "2%" section or somewhere else, but not into 5%.
Separately, you can still check all sorts of fractional values, for example,
1999.99 - is it 1999 or 2000? rounding in what direction, if any? Those. pay attention to data types. At least 1 test, if it is crooked, then it will be crooked everywhere.

But I don’t quite understand how to draw up test cases.

https://www.software-testing.ru/library/testing/ge...
As an example of design. If something specific is not indicated in your task, then google it and use the template.
Be sure to indicate what you enter (those examples) and what you expect from such answers.