This document discusses testing assumptions and potential issues when developing software. It recommends testing number bounds, stock levels, input values, and assumptions to implement useful "guards" that prevent errors. Conditional formatting and checks can verify values are within expected ranges.

1. Test your assumptions!

2. What could go wrong?

3. = what should you test!

4. Bounds for numbers can be tested

6. Can we sell more than there is in stock?

7. How to test?
There are two different ways

8. Conditional formatting

9. Checks

10. In software these are called ‘guards’

11. Guards

12. But, not all guards are useful ones

14. Other things to test

15. Assumptions

17. Input