Sandi Mentz 99Bottles Design Notes

Write tests, or think about tests when writing code.
This is a translation of the requirement in test form.

Consider the API structure to come up with the methods to be called in tests.

Principle: When a test becomes specific, the code should become more generic

When writing tests, when there is no fully formed idea on what the solution could be, we may write a test that taps the next logical value. eg: after testing for 99 bottles, maybe next would be test for 98 bottles. But dont be afraid to change the 98 test when it is identified that both of them fall in the same range and does not make a material test difference. Eg: Update the 98 test to 3, to push to the edge of that range. Often this may be driven by intuition and maybe formed by experience.

Focus on what your future self or another dev would look at. Attempt to reduce the cognitive load on that future self. eg: When using conditionals, consider, where appropriate, changing ifs to case, when there are multiple conditionals to indicate that the same value is being tested in each case.

Consider the responsibility of different methods to decide on how they are written. Eg: Why it is ok to have duplication in one method, while its not okay in another method

Use tests as a way of thinking and directing how the code is written. Sort of to box the thinking to an approach that is acceptable and clean.